At least 100 people were injured, 20 of them critically, when a powerful bomb reportedly ripped apart a passenger train late Sunday in the northeast Indian state of Assam, reported local media on Monday.

This took place in less than 12 hours after at least 35 people were killed and 200 injured in a major derailment of an express train in the northern Indian state of Uttar Pradesh.

No militant group has yet claimed responsibility for the attack on the train, according to Indo-Asian News Service.

The news service quoted a police spokesman as saying the explosion took place at 20: 30 p.m. local time, when the Guwahati- Puri Express was nearing Ghograpara in western Assam's Nalbari distict, about 70 km from Assam's main city of Guwahati.

Four coaches of the train derailed trapping scores of passengers, leaving many of them seriously injured, said the news service.

Police have found "flexible wires and other materials" used to trigger the explosion.

The train was bound for Puri in Orissa, eastern India.

VietNamNet/Xinhuanet