HONG KONG — The authorities in Taiwan said on Friday that they had ruled out organized terrorism in a bombing on a commuter train that left at least 25 people wounded.

The blast occurred on Thursday night in one of the train’s cars as it was approaching Taipei, the capital. The official Central News Agency cited witnesses describing an explosion followed by flames that spread in the car.

Most of the injuries were minor, but one person was in critical condition, the local news media reported on Friday morning, citing an official at a Taipei hospital. Two other people were reported to be in serious condition.

Central News Agency reported later Friday that one of the wounded, a 55-year-old man, had been identified as a suspect in the bombing. It said that his fingerprints had been found on the bomb, which the authorities had described as an 18-inch metal tube filled with an explosive substance. The report made no mention of a possible motive.