KOLKATA: At least seven people were killed when an express passenger train and a goods train collided Monday in India's West Bengal state, derailing three passenger carriages, police said.

Images on Indian broadcasters showed the tangled wreckage of carriages flipped on their side, and one thrust high into the air precariously balanced on another.

Police said rescuers were scouring the twisted carriages in case there were more bodies trapped beneath.

“We have confirmation of seven deaths and 39 passengers admitted at a local hospital with various injuries,“ local police officer Iftikar-Ul-Hassan told AFP.

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The incident is the latest to hit India's creaking rail network, which carries millions of passengers each day.

“We just saw the bodies of a dead driver and a guard... their bodies were taken out,“ Rajesh Kumar Singh, from the Railway Protection Force, told AFP.

“Some more bodies may be under the crash site, but we don’t yet know for sure.”

Prime Minister Narendra Modi offered his condolences to “those who lost their loved ones”, in a post on social media, adding that “rescue operations are underway”.

- 'Tragic' -

West Bengal’s Chief Minister Mamata Banerjee called the crash “tragic” in a post on social media.

“Doctors, ambulances and disaster teams have been rushed to the site for rescue, recovery, medical assistance,“ Banerjee said. “Action on war footing initiated.”

Banerjee said the crash took place in the Phansidewa area of Darjeeling district, when the Kanchenjunga Express train was hit by a goods train.

Railways minister Ashwini Vaishnaw said the “injured are being shifted to the hospital”.

India has one of the world's largest rail networks and has seen several disasters over the years, the worst in 1981 when a train derailed while crossing a bridge in Bihar state, killing an estimated 800 people.

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In June last year, a three-train collision killed nearly 300 people in Odisha state.

In recent years, India has been investing huge sums of money to upgrade the network with modern stations and electronic signalling systems.

On Sunday, a train crossed for the first time the world's highest railway bridge -- 359 metres (1178 feet) above a river -- in India's Himalayan region, the railways minister Vaishnaw said.

The arch-shaped steel structure over the Chenab River links sections of northern Jammu and Kashmir state, connecting the disputed territory to the rest of India.

Work on the railway track has been ongoing for nearly three decades, and the trial run comes ahead of a formal opening expected within weeks.