Taiwanese authorities have ruled out terrorism as the cause of a bomb attack on a commuter train which left at least 25 people injured. The incident took place on Thursday night (7 July) at Taipei's Songshan station and television images showed people with burnt limbs and faces.

"The people should keep calm, because this is not a terror attack," Taiwanese premier Lin Chuan said. "This is not an organised attack."

Police in Taiwan confirmed they had arrested a 55-year-old male suspect, named as Lin Ying-chang, according to South China Morning Post. He is reported to have been injured in the attack.

"According to a fingerprint found on a rectangular red backpack left in a train toilet along with a DNA sample we collected there, we believe one of the passengers injured in the blast could be the suspect," an official involved in the investigation said. Police added that they are looking into the suspect's motive.

A 50-year-old woman who suffered injuries to her hand during the attack said: "I saw a bag on fire when the train was approaching Songshan station and in no time the explosion occurred, blasting the train ceiling."

No organisation has yet claimed responsibility for the explosion and Railway Police Bureau spokesman Wang Bao-zhang said authorities had not received information which indicated it was a terrorist attack.

The explosive device is believed to be a 19-inch steel tube filled with pyrotechnic gunpowder, according to Reuters. One passenger recounted the pandemonium in the immediate aftermath of the explosion and told a local news channel: "There was a blast and the carriage went dark. People were panicking and screaming."

Four people are reported to be in critical condition.

Speaking earlier, Lin Chuan said: "It looks like somebody did this with a malicious intent and we will fully investigate this case."