Thousands of mourners gathered in Islamabad on Saturday to start burying the 31 killed in a suicide bombing at a Shi’ite Muslim mosque, as residents expressed concern that there could be further attacks.

A man opened fire at the Khadija Tul Kubra Imambargah compound on the outskirts of Pakistan’s capital, then detonated a bomb that killed 31, as well as himself, and injured more than 170 people. The Islamic State group claimed responsibility for the attack in a statement on the Telegram messaging app.

Funeral prayers for some of the victims were held in an open area near the mosque on Saturday morning under tight security, with police and a unit of elite commandos standing guard. Mourners beat their chests before stooping to lift the coffins and carry them toward the burial grounds.

“Whoever did this terrorism, may God burn them in hell and turn them to ash,” the prayer leader told mourners.

While bombings are rare in heavily guarded Islamabad, this is the second such attack in three months and, given the rise in militancy, there are fears of a return to violence in Pakistan’s major urban centres.

The government is “tracing the facilitators and handlers” behind the attack, said Information Minister Attaullah Tarar, adding that some victims remain critically injured in hospital and are “being provided the best healthcare possible.”

The bomber had a history of travelling to Afghanistan, Defence Minister Khawaja Asif posted on Friday on X, blaming neighbouring India for sponsoring the assault, without providing evidence.

India’s foreign office condemned the mosque attack and rejected the assertion that it had any involvement.

“It is unfortunate that, instead of seriously addressing the problems plaguing its social fabric, Pakistan should choose to delude itself by blaming others for its home-grown ills,” New Delhi said in a statement.

Shi'ites, who are a minority in the predominantly Sunni Muslim nation of 241 million, have been targeted in sectarian violence in the past, including by Islamic State and the Sunni Islamist group Tehreek-e-Taliban Pakistan.