[Updated at 9:35 a.m. ET] At least 162 people were injured in the accident, said Dr. Alberto Crescenti, head of the Medical Attention Emergency System, or SAME.
It took hours to free the remaining victims from the wreck, authorities said.
The cause of the collision was being investigated. Argentina's Transportation Secretary offered one early detail on the condition of the railroad crossing.
"The railroad crossing bar was working fine," Juan Pablo Schiavi said. Officials will also review video from the trains in their investigation, he said.
[Updated at 8:09 a.m. ET] At least seven people died when two trains and a bus collided in Buenos AiresÂ Tuesday, police said.
"There are seven confirmed deaths. There are people in hospital now in very grave state, including children. They have severe injuries," said Fernando Sostre, spokesman for the Argentine Federal Police.
Images broadcast on Argentine television showed dozens of police, fire and rescue workers combing through twisted metal and wreckage. Ambulances were seen transporting the injured to local hospitals.
[Updated at 7:45 a.m. ET] About 100 people were injured and two were trapped after a bus and two trains were involved in a collision, police said, according to the state-run Telam news agency reported. Initial reports of injuries were higher.
[Updated at 7:32 a.m. ET] At least six people died in a collision between two trains and a bus in Buenos Aires, the state-run Telam news agency reported, citing the city's fire chief.
About 170 people were injured and dozens more were trapped after a bus and aÂ two trains were involved in a collision, police said.
A train rammed into a bus at a street-level train crossing, causing the train to derail, where it was struck by a second train, the state-run Telam news agency reported.
[Updated at 7:23 a.m. ET] Some 170 people were injured and dozens remain trapped after a bus and a train collided in Buenos Aires, Argentina Tuesday morning, police said.
At least seven people were "very seriously" injured, Argentine Federal Police spokesman Fernando Sostre said.
Children are among those injured, he said.
The crash happened at 6:15 a.m. (5:15 a.m. ET) in the Flores district of Buenos Aires.
This story is developing. We'll bring you the latest information as soon as we get it.
What is a bus-train? I would not ride one!
Buenos Aires is as dangerous as NYC or Los Angeles or Detroit or Miami. That is, the only difference is that spanish is spoken all the time instead of sometimes. What this appears to be (check out clarin.com) is a flawed train alert system at a crossing caused by poor maintenance. The lights were blinking, but the barrier wasn't all the way down. The bus driver could be at fault as the lights were blinking warning, but the greater blame may have to rest on whomever or whatever maintains the railroad crossing system.
Love Buenos Aires. Am from NYC. I grieve for these people and hope there is recompense for this horror.
Wow, this is terrible. They need more gun control in argentina, why would there government let this,oh...wait, a train did this not guns? Huh, well apparently trains are just as dangerous so no one should be allowed to use trains except the military and police. That will fix this problem.