Deadly train crash near Buenos Aires
At least three people have been killed and 315 injured in a rush-hour train crash in the outskirts Buenos Aires, Argentine officials say.
The accident happened near the Castelar station, about 30km (19 miles) west of the capital, when a commuter train hit another empty, stationary train.
Rescue crews and volunteers went to the scene to help the injured, who were taken to nearby hospitals.
The cause of the crash is still being investigated.
Media reports say that the moving train may have had faulty brakes.
But Transport and Interior Minister Florencio Randazzo said the train "had new brakes".
"We want to establish whether it was an accident or an attack," said Mr Randazzo.
Yellow light ignored
The two train drivers have been detained. Blood alcohol content tests showed they were sober, said the minister.
"The train stopped in three previous stations without any problem," Mr Randazzo explained.
"But after the train left Moron station, its speed continued to rise, even when it passed a yellow light where it should have slowed down."
The crash happened in the morning rush hour, at 07:07 local time (10:07 GMT).
"I heard a loud noise and everyone started falling down, and people were shocked and crying," 26-year-old passenger Lida was quoted as saying by the AFP news agency.
The two trains did not leave the rails after the incident on the Sarmiento line.
Mr Randazzo said most survivors have been discharged, but more than 30 are still in hospital - some remain in a serious condition.
There were many cases of severe fracture, which could have caused life-threatening vascular damage.
In February last year, 51 people died and more than 700 were injured in a train crash on the same line.
The authorities later revoked a local company's right to operate trains on the line and pledged to make new investments in safety.
Commuters complain of frequent delays and bad service and it is not uncommon to see travellers crammed into trains on their way to work, says the BBC's Ignacio de los Reyes in Buenos Aires.