At least three people have been killed and several injured in a blast on a train in the Indian state of Jammu and Kashmir.

"The blast occurred in the Sealdah Express in Baira, 30km south of Jammu," a police spokesman is quoted as saying by the French news agency AFP.

"The train was travelling to the eastern city of Calcutta. Ten of the injured are in a critical condition," the spokesman said.

The blast took place in an air-conditioned carriage of the train minutes before it was due in Samba, according to the Press Trust of India.

Seven carriages were reported to have been derailed by the blast.

The police suspect militants planted the bomb, but no group has so far said it carried out the attack.

Gun attack

Earlier, police in Kashmir said six people had been killed, and three others injured by unidentified gunmen in the town of Pattan, 30km from the capital, Srinagar.

The gunmen entered the home of a police official and shot him dead along with two of his daughters.

The two women were working as special police officers attached to the security forces, according to the Press Trust of India.

The attackers later killed three people in another village, the report said.

It is not known who carried out the killings, although police suspect the attack was the work of separatist militants.

However, there was tension in the area as police launched a hunt for the killers.

One report said residents blocked a road, and shouted anti-Indian slogans saying that the killings were carried out by Indian security personnel.

Clinton visit

On Wednesday, US President Bill Clinton said South Asia was one of the most dangerous places in the world because of the Kashmir dispute between India and Pakistan.

The president said he hoped to help ease the tension between the two nuclear neighbours when he visited the region next month.

The Indian Government blames Pakistan for backing militants in Indian-administered Kashmir.

Pakistan denies the charge, and says it only offers moral and diplomatic support to Kashmiri separatists.