[Updated at 4:54 p.m.] An agreement has been reached in the U.N. Security Council to release $1.5 billion in frozen Libyan assets to the country's fledgling rebel government, diplomats said Thursday.

[Updated at 2:13 p.m.] Gadhafi loyalists have destroyed an empty Libyan airline passenger plane parked at the international airport in Tripoli.

[Updated at 11:54 a.m.] A message purportedly from Moammar Gadhafi was aired Thursday on a loyalist radio station.

The speaker urged people not to leave Tripoli "for the rats." It further implored listeners to "Go out into the streets and fight."

CNN cannot independently confirm the authenticity of the recording. Gadhafi has previously described his adversaries before as rats.

[Updated at 10:49 a.m.] The main source of the opposition's supplies is coming from fighters loyal to Gadhafi. As the rebels win battles, they gather up the enemy's weaponry and equipment to add to their own arsenal.

In Ras Lanuf, home to an oil refinery capable of producing hundreds of thousands of barrels of oil a day, a long line of trucks awaited refueling. Most of the trucks had been taken from Moammar Gadhafi's loyalists and been retrofitted with heavy weaponry, including anti-aircraft guns and a rocket launcher.

Ras Lanuf is about 125 miles from Sirte, Gadhafi's hometown and one of the Libyan leader's last strongholds.

Gadhafi has a $1.4 million bounty on his head, but despite claims that he is holed up in an apartment complex in Tripoli, observers are skeptical because of a past rebel assertion that they knew where the Libyan leader was hiding and another announcement that they had captured his son, Saif al-Islam. Neither were accurate.

[Updated at 10:15 a.m.] There has been sporadic but intense artillery fire throughout day near Tripoli International Airport as rebels try to capture the highway connecting the airport and the capital. The airport is about 17 miles south of the capital.

[Updated at 10:09 a.m.] It is difficult to tell exactly what is happening on the ground because while there are legitimate firefights taking place, there is also plenty of celebratory gunfire, including from the rebels' large-caliber, anti-aircraft guns.

CNN's Dan Rivers, however, said there was a fierce firefight in one corner of Moammar Gadhafi's compound about two hours ago.

[Updated 10:02 a.m.] Smoke can be seen rising from Bab al-Aziziya, the Libyan leader's compound.

[Posted at 9:46 a.m.] Rebels say they believe Libyan leader Moammar Gadhafi is at an apartment complex near his compound in Tripoli, a rebel commander said Thursday.

The commander told CNN that more troops have been dispatched to surround the building.

Rebels say they believe the leader of more than four decades may be holed up with some of his sons.

CNN has not been able to confirm the rebels' claim independently. Rebels have made many bold statements in recent days, some of which haven't turned out to be true.

The rebels did not explain why they believe it is Gadhafi inside the apartment buildings, where Reuters reports rebels are trading gunfire with the leader's loyalists.

"They are together. They are in a small hole," one of the fighters involved in the battle, Muhammad Gomaa, told Reuters. "Today we finish. Today we will end that."