At least 21 people were injured in an explosion last night in a commuter train cabin in Taipei's Songshan Railway Station, in what is believed to be the worst train blast on the island.
The train was travelling from the north-western city of Hsinchu to the north-eastern port city of Keelung, some three hours away.
It is not clear what caused the blast but National Police Agency director-general Chen Kuo-en said that for now, it appears that it is not likely to be a terrorist attack.
Witnesses said they heard three blasts inside the cabin before it burst into flames.
They saw a man who walked in and left a bag in the cabin moments before the explosion.
A 20cm-long black object was found on the train seat, according to police.
Mr Chen said the object "looked like a firecracker", reported Central News Agency. Some witnesses said they smelled gunpowder.
Taipei's Fire Department said it received a message about the explosion at around 10pm and sent more than 10 ambulances and 10 fire engines to the scene. The fire was then extinguished.
The city's police officers are on the hunt for the suspect. Witnesses said he is believed to be in his 40s.
Premier Lin Chuan has ordered relevant government agencies to form a team to investigate the explosion and to help the victims get the best medical attention, Cabinet spokesman Tung Chen-yuan said.
Medical staff said four people are seriously hurt, including a 14-year- old boy who sustained second- to third-degree burns on his face.