A suicide attack struck a Shiite mosque in eastern Afghanistan Friday targeting worshippers during weekly prayers, with officials warning of multiple casualties in the latest incident to hit the minority.

“A suicide blast took place inside a Shiite mosque in the city of Gardez of Paktia province. There are casualties from the blast, but we don’t know how many for now,” General Raz Mohammad Mandozai, provincial police chief of Paktia, told AFP.

Wilayat Khan Ahmadzai, head of the Gardez public health department, confirmed the attack and fears over mounting casualties.

“We have received 60 wounded worshippers and four dead at the civilian hospital in Gardez,” said Ahmadzai.

The attack comes as urban areas across Afghanistan have been rocked by an increasing number of attacks in recent months, with both the Islamic State (IS) and Taliban insurgents targeting security forces and government installations.

The Taliban has not claimed a major attack in a city for weeks as it comes under increased pressure to agree to peace talks with the Afghan government.

But IS has carried out multiple attacks in the eastern city of Jalalabad and the capital Kabul in recent months, targeting everything from government ministries to a midwife training centre.

Last month an IS suicide bomber blew himself up near Kabul international airport, killing 23 people including AFP driver Mohammad Akhtar.

The increased attacks come as US and Afghan forces intensify ground and air offensives against IS, and the Taliban step up their turf war with the group.