Indian Railways Minister Mamata Banerjee has blamed neighbouring Pakistan for a bomb which derailed a train in the Indian state of Jammu and Kashmir, killing five people.

The explosion which ripped apart a stretch of track also wounded about 20 people.

Two people died immediately and three died later of their injuries. The victims included an infant and a paramilitary soldier.

The blast took place on Thursday evening on the main railway line between Delhi and Jammu.

Ten coaches of the Sealdah Express bound for Calcutta were derailed, minutes before the train was due in Samba.

Services on the line have been suspended.

No accident

"This is not a train accident, this is a bomb blast staged by the Pakistanis," Ms Banerjee said after visiting the site of the explosion on Friday, adding that this section of railway track - only 4km (2.5 miles) from the border - had been targeted before.

She said the state government in Kashmir had last month requested a series of security posts to be built along the track.

Police said the attackers had planted their powerful bomb underneath a small bridge and triggered the device as the train was passing overhead.

A police official said 13kg (30 lbs) of unused plastic explosives had been recovered from the site of the attack.

"We think they were planning to use these as well," an official said.

S K Dikshit, whose wife died in the explosion, said: "She was sitting in the lower berth. Suddenly there was a deafening noise and I saw her body rise up to the ceiling. When I looked down, she was dead."

More than 25,000 people have been killed in violence linked to the insurgency launched in Kashmir in 1989.

Kashmir, India's only Muslim-majority state, is claimed by both India and Pakistan and has been the cause of continued tension since independence in 1947.