At least 17 soldiers have been killed in Pakistan after a train carrying hundreds of army personnel derailed from a bridge and plunged into a canal.

The army said four carriages derailed after part of the bridge collapsed near Wazirabad in Punjab province.

The cause of the collapse was not clear. Reports said the bridge had been built in the British colonial era.

Khawaja Saad Rafique, Pakistan's railways minister, suggested sabotage may have been involved in the accident.

"It seems like some other hand must be involved because derailment does not happen like this," he told local media.

Rafique called the incident "unprecedented".

"It could either be a case of a blast or someone has tried to loosen the fish-plate on the track," he told Karachi's Geo TV.

The dead reportedly included a senior officer, his wife and daughter.

A preliminary report would be issued on Thursday night, followed by a more detailed report within 72 hours, he said.