Eighteen people have been injured after a grenade exploded at a bus station in the Indian city of Jammu, in the restive state of Jammu and Kashmir.

Police suggested the blast could have been aimed at fomenting tensions between different communities in Jammu city, home to about half a million people.

“It seems that the grenade was lobbed from outside [the premises] and it rolled under the bus and caused injuries to approximately 18 people,” said a police official, MK Sinha.

A second police officer said: “A grenade was hurled by an unidentified person which exploded under a bus in the main terminal. The bus was about to leave to Pathankot city in Punjab.”

Tensions between India and Pakistan have been high after 40 Indian troops were killed in a suicide bombing on 14 February in the part of Kashmir that Delhi controls. The attack was claimed by Jaish-e-Mohammed (JeM), a militant group based in Pakistan. India has long accused Islamabad of supporting the insurgents.

In response, India said it carried out airstrikes on 26 February on what it called a JeM training camp at Balakot inside Pakistan. The Pakistani government said no sites or targets had been hit, and on 27 February Islamabad launched its own airstrike. In an ensuing dogfight at least one Indian aircraft was shot down and the pilot was captured by Pakistan.

As fears rose that the two nuclear-armed nations might enter their fourth war, Pakistan released the pilot in what it called a “gesture of peace”. This helped ease tensions, although both countries have continued to fire artillery and mortars over their de-facto border, the line of control, killing civilians on both sides. Indian forces have also fought gun battles with militants and arrested hundreds of people.

Jammu is largely a Hindu-dominated area of the disputed Himalayan region that is ruled by India and Pakistan in parts but claimed by both. It has witnessed several incidents of militant attacks in the past despite little to no support for armed rebels who enjoy widespread public backing in the Kashmir region.

Most of the attacks have been targeted at military installations, including a strike by JeM militants on an army base in the Sunjuwan area in February 2018 that left 11 people dead, including six soldiers and four attackers.

Indian police imposed a curfew for several days in Jammu in the wake of last month’s attack after mobs attacked and set fire to properties belonging to Kashmiri Muslims.