A grenade blast at a bus station in the Indian city of Jammu has killed one civilian and injured at least 30 people, police have said.

Authorities called for calm following the explosion on Thursday morning, which comes weeks after a Pakistan-based militant group killed 40 Indian paramilitary police in Kashmir.

Jammu is the winter capital of India’s Jammu and Kashmir state, part of which is claimed by Pakistan.

“I request everybody to maintain calm,” the city’s police chief MK Sinha said. “We are chasing all leads.”

Footage posted on social media showed injured victims lying on the ground following the blast, which went off just before noon local time (6.30am GMT). Police said the grenade had rolled under bus after being hurled at the station.

Grenade attack injures at least 18 in Kashmir: in pictures Show all 10 1 /10 Grenade attack injures at least 18 in Kashmir: in pictures Grenade attack injures at least 18 in Kashmir: in pictures Glass shattered in the explosion litters the floor around the bus in Jammu, India AFP/Getty Grenade attack injures at least 18 in Kashmir: in pictures Policemen inspect the bus that was subject of a grenade attack in Jammu, India AFP/Getty Grenade attack injures at least 18 in Kashmir: in pictures A sniffer dog and policemen inspect the site of a grenade attack in Jammu, India AP Grenade attack injures at least 18 in Kashmir: in pictures Policemen and onlookers stand at the site of a grenade blast in Jammu, India Reuters Grenade attack injures at least 18 in Kashmir: in pictures People injured in a grenade attack are treated at the government medical hospital in Jammu, India AP Grenade attack injures at least 18 in Kashmir: in pictures Policemen inspect the site of a grenade attack in Jammu, India AP Grenade attack injures at least 18 in Kashmir: in pictures A person injured in a grenade attack is carried for treatment to a government medical hospital in Jammu, India AP Grenade attack injures at least 18 in Kashmir: in pictures People injured in a grenade blast are taken to the hospital for treatment in Jammu, India Reuters Grenade attack injures at least 18 in Kashmir: in pictures Policemen inspect the bus that was subject of a grenade attack in Jammu, India AFP/Getty Grenade attack injures at least 18 in Kashmir: in pictures Indian police stand guard at the site of a grenade blast at a bus station, with blood splatters pictured on the floor, in Jammu on March 7, 2019. - Eighteen people were injured on March 7 when a grenade exploded at a bus stop in the Indian city of Jammu, part of the restive state of Jammu and Kashmir, police said. (Photo by Rakesh BAKSHI / AFP)RAKESH BAKSHI/AFP/Getty Images AFP/Getty

“It was a big blast,” a witness told news agency ANI.

No arrests have been made over the explosion, the third grenade attack in Jammu the past 10 months. No one was hurt in the last blast in December.

Authorities have blamed rebels fighting against Indian rule in Kashmir for previous attacks, often without producing any evidence. Rebels in turn accuse government agents of carrying out false flag attacks to turn people against their movement.

Tensions have increased in the region in recent weeks after India carried out airstrikes in Pakistan against militants blamed for killing paramilitary police in a 14 February suicide bombing.

Last week, Pakistan shot down an Indian fighter jet and captured its pilot, who was later returned in what was described as a “peace gesture”.

Both countries have blamed each other for “unprovoked” violations of a 2003 ceasefire at several sectors of the Kashmir border.

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On Thursday, the leader of a hardline Hindu group in India justified an attack on two fruit sellers from Muslim-majority Kashmir as revenge for February’s suicide bombing.

The street traders were beaten with sticks in the northern city of Lucknow on Wednesday by members of the right-wing Vishwa Hindu Dal.

“After the attack on our army men with the help of Kashmiri jihadis, there is anger among the public,” said the group’s leader, Ambuj Nigam.

While the nuclear-armed Indian and Pakistani militaries have clashed along their disputed border, many ordinary Indians have turned their anger on Kashmiris, who live throughout the country.

In Pakistan, the government announced it had taken control of 182 religious schools and detained more than 100 people as part of its push against banned groups.

The country has come under international pressure to act against groups carrying out attacks in India, including Jaish-e-Mohammed, which claimed responsibility for the attack on paramilitary police.

Thursday’s raids is Pakistan’s biggest move against banned groups in years and appeared to be targeting Islamic welfare organisations that the US says are a front for militant activities.