New Delhi  - At least 15 passengers were killed when an express train rammed into the back of another train near India's northern city of Mathura on Wednesday, media reports said.

While 15 bodies had been pulled out from the train at the site of the crash outside Mathura, 140 kilometres south of New Delhi, as many as 45 passengers were trapped in the wreckage, the NDTV network reported quoting railway officials.

Twenty passengers injured in the crash were moved to a state-run hospital in the city.

Railway officials told the news channel that the collision occurred at about 5:30 am (0000 GMT) when the Goa Express crashed into the back of the stationary Mewar Express outside Mathura station.

"We do not know the exact cause but an inquiry will soon be instituted to investigate the accident," Indian Railways spokesman RD Vajpayee said.

Senior district officials, police and firemen were conducting rescue operations, using blowtorches to cut through the metal and windows to rescue passengers inside.

The Indian army was also called to assist in the rescue efforts.

"We felt a strong impact and were jolted out of sleep. Many passengers fell onto the tracks because of the crash," a survivor told NDTV.

Railway traffic on the busy route was suspended as a result of the accident. Several express trains plying the segment were diverted or cancelled, railway authorities said. (dpa)