The latest developments on the situation in Libya, where the government declared a cease-fire Friday after the United Nations voted to impose a no-fly zone in response to weeks of bloody clashes between forces loyal to Moammar Gadhafi and rebels. Read our complete story and check out our full coverage on unrest in the Arab world. Also, don't miss a gripping, high-resolution gallery of images from Libya.

[9:50 p.m. ET, 3:50 a.m. in Libya] A woman in Tripoli says she was awoken this morning by a loud explosion from a nearby military base.

After being shaken from her sleep around 2:20 a.m., she said she heard gunfire and went to the roof of her building to observe.

"Then I heard the second explosion," she said. She saw fire rising up from the direction of Mitiga Airport, formerly known as the U.S. Wheelus Air Base.

She also said that people continue to live in fear of Gadhafi. "They're afraid to come out because when they do, he attacked them very, very severely," she says. "This is putting terror in all neighborhoods."

[9:30 p.m. ET, 3:30 a.m. in Libya] State TV in Libya reported early Sunday that 48 people were killed and 150 injured in coalition airstrikes. CNN was not immediately able to independently confirm the report.

[9:20 p.m. ET, 3:20 a.m. in Libya] Britain's Royal Air Force the RAF has launched Stormshadow missiles from a number of Tornado GR4 fast jets as part of a series of coordinated coalition strikes against Libya, the Ministry of Defense said.

"We made clear that if Gaddafi did not comply with the UN Security Council Resolution 1973, it would be enforced through military action. Our Armed Forces have therefore participated in a co-ordinated international coalition strike against key military installations," defense secretary Liam Fox said in a statement.

"The fast jets flew 3,000 miles from RAF Marham and back making this the longest range bombing mission conducted by the RAF since the Falklands conflict," he said. "HMS Westminster is off the coast of Libya and HMS Cumberland is in the region ready to support operations. Typhoon aircraft are also standing by to provide support."

[9:10 p.m. ET, 3:10 a.m. in Libya] Benghazi remains eerily quiet but tense after a day of fights between Gadhafi supporters and opposition fighters, CNN's Arwa Damon reports.

Anti-Gadhafi forces in Benghazi were buoyed by the international intervention but still expect more to come from Gadhafi.

"This is not yet a victory for them. They expect Gadhafi forces to carry something out again, they do not think this is over," she said. "People do not take Gadhafi's threats lightly. They have learned from four decades of his rule. They expect him to plan some kind of maneuver."

[8:45 p.m. ET, 2:45 a.m. in Libya] It is now mostly quiet in Tripoli, just minutes after sustained anti-aircraft gunfire, Robertson reports.

[8:33 p.m. ET, 2:33 a.m. in Libya] Heavy anti-aircraft gunfire can be heard in Tripoli, CNN's Nic Robertson reported.

Robertson said anti-aircraft gunfire also was heard a few hours ago, but it is now more intense. The current round followed a couple of loud explosions, Robertson reported from Tripoli.

[8:26 p.m. ET, 2:26 a.m. in Libya] The Department of State has issued a statement reminding media organizations that no U.S. officials remain in Libya, limiting its ability to provide assistance to U.S. citizens or other employees of U.S.-based news organizations. The State Department continues to advise against travel to Libya and urges U.S. citizens already in Libya to depart immediately.

[7:41 p.m. ET, 1:41 a.m. in Libya] After delaying his trip to Russian, U.S. Defense Secretary Robert Gates has been keeping a close eye on the situation in Libya, a Pentagon spokesman said.

"Secretary Gates has been in near constant contact with the Joint Staff as planning for Operation Odyssey Dawn has evolved. He has conducted multiple individual and conference with National Security Adviser Donilon and President Obama. And, of course, he continues to receive a steady flow of operational and intelligence information," spokesman Geoff Morrell said.

[6:20 p.m. ET, 12:20 a.m. in Libya] A defiant Moammar Gadhafi says missile strikes launched Saturday night are grounds for a "crusade war" and vowed to fight back.

"The Libyan people will fight against this aggression. All you people of the Islamic nations and Africa. And all you people in Latin America, and asia to stand with the Libyan people in its fight agaist this aggression," he said.

"France has carried an aggression against Libya. The security council and the international community has a responsibility to do what it takes about this aggression against the sovereign state."

[6:01 p.m. ET, 12:01 a.m. in Libya] Hours after coalition forces launched the first wave of attacks against his military forces, Libyan leader Moammar Gadhafi said his people will fight back against undeserved "naked aggression."

Libyan state TV broadcast Gadhafi's response, which included a call for people to take arms in the "war zone."

[5:45 p.m. ET, 11:45 p.m. in Libya] Moammar Gadhafi is due to make an address soon, according to media reports citing Libyan TV.

[5:36 p.m. ET, 11:36 p.m. in Libya] Russia reacted "with regret" Saturday to the start of international military action in Libya, urging an end to violence on all sides.

It said the United Nations resolution that authorized the use of force had been "hastily adopted."

"We again urge all Libyan sides, as well as the participants of the military operation, to do everything they can to prevent the suffering of innocent civilians and to ensure a speedy cease-fire and an end to violence," the Russian Foreign Ministry said in a statement.

[5:04 p.m. ET, 11:04 p.m. in Libya] Armed police are gathering outside government buildings in Tripoli and the streets are mostly clear of the revelers that had gathered earlier Saturday evening, CNN's Nic Robertson said.

Earlier, people were playing music and dancing in the street outside Gadhafi's palace compound in an apparent show of celebration, Roberston said. The missile strikes were inaudible over the music and revelry, he said.

[5:04 p.m. ET, 11:04 p.m. in Libya] Coalition strikes were launched despite a government-initiated cease-fire and "major reforms in economic and organizational contexts," a Libyan government spokesman says.

"The claim that this aggression is for the protection of civilians is contradicted by what has really happened on the ground tonight."

[5:04 p.m. ET, 11:04 p.m. in Libya] President Obama is planning for the U.S. portion of the military action in Libya to only last for a few days, according to a senior administration official.

"In terms of the heavy kinetic portion of this military action, the president envisions it as lasting days, not weeks," said the senior official. "After that we'll take more of a supporting role."

[4:58 p.m. ET, 10:58 p.m. in Libya] Air attacks on several locations in Tripoli and Misrata have caused "real harm" to civilians, a Libyan government spokesman said Saturday.

"I am very sorry and saddened that my country is facing a barbaric and armed attack," the spokesman said, adding that "this aggression will not weaken our spirits."

[4:28 p.m. ET, 10:28 p.m. in Libya] More than 110 Tomahawk cruise missiles were fired from U.S and British ships and submarines, striking more than 20 integrated air defense systems and air defense facilities ashore, a Joint Chiefs of Staff official said Saturday.

The goals of "Operation Odyssey Dawn" are to prevent further attacks on Libyan citizens and opposition groups and to degrade the capability of Moammar Gadhafi's forces to resist a no-fly zone, Vice Admiral William E. Gortney Director said.

The strikes were carefully coordinated based on an assessment of whether the targets posed a direct threat to coalition pilots or to the people of Libya, he said.

"This is an international military effort urged by the Libyan people themselves and other Arab nations," Gortney said, noting that U.S. military forces are on the "leadership edge" of the operation.

"This is just the first phase of what will likely be a multi-phase designed to enforce the U.N. Security Council resolution."

[4:10 p.m. ET, 10:10 p.m. in Libya] U.S. President Barack Obama said military action in Libya is not an outcome the United States had sought.

"The use of force is not our first choice, and it is not a choice I make lightly," he said in an audio message from Brazil. "But we cannot stand idly by when a tyrant tells his people that there will be no mercy and his forces step up their assault."

He also said the United States will not deploy any U.S. troops on the ground on Libya. Obama emphasized that the United States was acting as part of a broad coalition of U.S. allies to enforce the U.N. Security Council resolution, and not unilaterally.

"The writ of the international community must be enforced," he said. "We are answering the calls of a threatened people and we are acting in the interests of the United States and the world."

[3:55 p.m. ET, 9:55 p.m. in Libya] The U.S. military has launched its first missiles in Libya against Moammar Gadhafi's forces in the western part of the country, a senior Defense Department official said Saturday.

U.S. Tomahawk missiles landed in the area around Tripoli and Misrata, the official said, adding that the action was taken after Gadhafi failed to comply with a cease-fire.

The first part of the multi-phase approach will be to degrade air defenses, CNN's Chris Lawrence reports, citing the Defense Department official. Most of the first strikes will be concentrated around Tripoli and Misrata, specifically to take out his air defenses. Ground forces will be targeted as well because they carry capability to shoot down planes, the official said.

[3:44 p.m. ET, 9:44 p.m. in Libya] British Prime Minister David Cameron said military action was necessary to enforce the cease-fire and prevent Moammar Gadhafi from attacking his people.

"What we are doing is necessary, it is legal and it is right," he said. "I believe we should not stand aside while this dictator murders his own people."

[2:32 p.m. ET, 8:32 p.m. in Libya] A U.S. defense official said the United States is poised to launch cruise missiles from warships in the Mediterranean Sea, and that these strikes would target Moammar Gadhafi's air defenses. The United States is prepared to "defend its allies flying over Libyan airspace and enforce the no-fly zone," the official said.

[1:15 p.m. ET, 7:15 p.m. in Libya] French planes fired on a Libyan military vehicle Saturday evening, according to the French Defense Ministry.

[12:43 p.m. ET, 6:43 p.m. in Libya] The United States is standing with its allies and partners in enforcing the U.N. resolution on Libya, and it is also behind the Libyan people, Secretary of State Hillary Clinton said Saturday. "We will stand with the people of Libya and we will not waiver (in our effort) to protect them," she said.

[12:39 p.m. ET, 6:39 p.m. in Libya] Secretary of State Hillary Clinton praised the Arab League's stance on Libya, saying it "changed the diplomatic landscape." The group last week approved the establishment of a no-fly zone in Libya.

[12:36 p.m. ET, 6:36 p.m. in Libya] The Libyan government "has lost all legitimacy," Secretary of State Hillary Clinton said Saturday, adding that the international community is right to enforce immediately the United Nations resolution. "Further delay will only put more civilians at risk," she said in Paris.

[12:34 p.m. ET, 6:34 p.m. in Libya] Secretary of State Hillary Clinton said that despite talk of a cease-fire from Libya, Moammar Gadhafi "continues to defy the world." "His attacks on civilians go on," she told reporters Saturday.

[11:04 a.m. ET, 5:04 p.m. in Libya] The French air force is opposing any aggression by Libyan leader Moammar Gadhafi against the population of rebel-held Benghazi, French President Nicolas Sarkozy said Saturday. "As of now, our aircraft are preventing planes from attacking the town," Sarkozy said. "Our French aircraft are ready to intervene against tanks."

[10:58 a.m. ET, 4:58 p.m. in Libya] Countries attending a meeting in Paris sent Libyan leader Moammar Gadhafi a warning, French President Nicolas Sarkozy said Saturday.

"If there is not an immediate cease-fire and withdrawal of the forces that have been attacking civilian populations in the last few weeks, our countries will have recourse to military means," Sarkozy said. Sarkozy said the warning was endorsed by all participants at the Paris summit.

Libya's population "must not be deprived of its rights by violence and terror," Sarkozy said. "There is still time for Colonel Gadhafi to avoid the worst, by complying immediately and unreservedly with all the demands of the international community. The doors of diplomacy will open once again when the aggression stops."

[10:51 a.m. ET, 4:51 p.m. in Libya] U.S., European and Arab leaders met Saturday at a last-minute Paris meeting on Libya.  "There is minute-by-minute consultation between the United States and the militaries of other countries that are considering their support of action" under a U.N. resolution authorizing the use of force, a senior State Department official told reporters.

[10:40 a.m. ET, 4:40 p.m. in Libya] A French official confirms that French fighter jets are flying over Libya.

[9:55 a.m. ET, 3:55 p.m. in Libya] Moammar Gadhafi's military forces pushed into the rebel stronghold of Benghazi on Saturday. Artillery rounds landed inside the city, and pro-Gadhafi tanks rolled into the town firing rounds, witnesses said. Plumes of smoke rose in Benghazi as civilians said buildings came under small arms fire.

[7:35 a.m. ET, 1:35 p.m. in Libya] Oil production has been dropping and Libya wants foreign and Libyan employees to go back to the oil fields, Libyan oil minister Shukri Ghanem told reporters Saturday.

[6:19 a.m. ET Saturday, 12:19 p.m. in Libya] Libyan leader Moammar Gadhafi's government on Saturday sent harsh messages to leaders such as U.S. President Barack Obama and French President Nicolas Sarkozy. "You have no right ever to intervene in our internal affairs," said a letter read by Libyan government spokesman Musa Ibrahim. The letter also said the government would never fire "a single bullet" against its citizens. Gadhafi's government continued to blame the conflict in Libya on al Qaeda.

[6:05 a.m. ET Saturday, 12:05 p.m. in Libya] A CNN team saw tanks belonging to forces loyal to Moammar Gadhafi enter Benghazi on Saturday, and observed rebel tanks moving to confront them. Tank, mortar and artillery fire echoed across the city, interspersed with sustained bursts of small arms fire. Plumes of smoke could been seen rising above Benghazi.

[4:35 a.m. ET Saturday, 10:35 a.m. in Libya] CNN journalists observed tanks moving north from 5 kilometers south of Benghazi and other tanks moving through the western part of the city. It is not known which side the tanks belonged to. The journalists also saw tank and artillery rounds land inside the city.

[3:56 a.m. ET Saturday, 9:56 a.m. in Libya] A fighter jet was shot down and burst into flames Saturday in the area of Benghazi. Meanwhile, explosions could be heard in the city, which has been a stronghold for rebels opposing Libyan leader Moammar Gadhafi. It was not immediately clear who the fighter jet belonged to. Rebels have vowed to defend Benghazi to the death.

On Friday, the Libyan government said it was abiding by a cease-fire, but witnesses have said violence from pro-Gadhafi forces has continued.

[12:23 a.m. ET Saturday, 6:23 a.m. in Libya] Agence France-Presse reported airstrikes and explosions Saturday morning in an area southwest of Benghazi. CNN had not independently confirmed the report.