More than 200 passengers were injured in the Malaysian capital Kuala Lumpur on Monday when two metro trains collided in a tunnel, police said.
The accident happened just before 9:00 pm (1300 GMT) when a packed train collided with a second that was empty and heading in the opposite direction.
Pictures circulating on social media showed injured passengers sprawled on the floor of a carriage, which was covered in glass.
Forty-seven people suffered serious injuries and 166 had minor injuries, said police official Mohamad Zainal Abdullah.
There was no sign of foul play and the accident could have been caused by miscommunication, he said.
Prime Minister Muhyiddin Yassin said on Facebook that the crash was "serious".
"I have instructed the transport minister and (train) operator… to conduct an in-depth probe to find out the cause of the accident," he said.
Accidents are rare on the metro system that serves Kuala Lumpur.