A grenade blast at a bus station in the Indian-controlled portion of Kashmir has left one civilian dead and at least 30 others injured.

Police said the grenade was hurled at the main bus station in Jammu city and rolled beneath a bus, where it exploded.

Four people were taken to hospital in a critical condition, and one of them later died from their injuries.

Kashmir attackPolice inspect the site of the grenade attack in Jammu city (Channi Anand/AP)

Police are investigating who was responsible for the blast.

In the past, Indian authorities have blamed rebels fighting against Indian rule in the disputed region for similar grenade attacks, often without producing any evidence.

Rebels have in turn accused government agents of carrying out the attacks to defame their movement.

Jammu, a Hindu-majority city, experienced days of protests following a suicide bombing in the Indian-held portion of Kashmir on February 14 that killed 40 Indian paramilitary soldiers, the deadliest attack against Indian forces since the start of an armed rebellion in 1989.

Kashmir attackA sniffer dog is used by police investigating the attack (Channi Anand/AP)

Hundreds of Hindu nationalists attacked Muslim neighbourhoods in the city, burning vehicles and hurling rocks at homes. Authorities imposed a curfew for several days in the city.

About 70,000 people have been killed in the uprising and the ensuing Indian crackdown since 1989.