At least two people are reported to have been killed and several injured in a blast on a train in Indian-administered Kashmir.

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

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

Police have rushed to the site of the explosion and launched an investigation, the reports say.

More details are expected soon.