Updated

Pakistani officials stepped up security across the country on Monday after two suicide bombers stormed a church packed with worshippers attending pre-Christmas service, killing 9 people and injuring dozens of others — an attack the Islamic State claimed responsibility for on Sunday.

A group funeral was held on Monday afternoon after a service by Bishop Sadiq Daniel at Quetta's Christian cemetery. About 400 people were attending the service at Bethel Memorial Methodist Church in Quetta, the capital of southwestern Baluchistan province, on Sunday when the assault happened. About 60 people were also injured.

pakistan suicide bombing church

At least nine people were killed when two suicide bombers attacked the church during pre-Christmas service. (Copyright 2017 The Associated Press. All rights reserved.)

Sunday’s incident was the first attack on a church claimed by an ISIS affiliate in Pakistan. ISIS-run Aamaq news agency said in a statement two "martyrdom-seeking fighters clad in explosive vests and carrying machine guns and hand grenades attacked the church."

The two suicide bombers charged police guards outside the church, triggering a gun battle. Police killed one assailant, but the other suicide bomber made it to the entrance of the prayer hall and opened fire at worshippers before detonating his explosive vest.

PAKISTAN-ATTACK/

A group funeral was held on Monday for the victims in the deadly suicide bombing at the church in Pakistan. (Reuters)

SUICIDE BOMBERS ATTACK PAKISTAN CHURCH, KILLING AT LEAST 9, OFFICIALS SAY

"We were praying when a bullet hit me," Naseem Masih told The Associated Press.

ISIS called the attacker who detonated his vest one of the “Crusaders” and said the other was killed while fighting “renegade Pakistani security forces.”

f08b36b9-PAKISTAN-ATTACK/

A policeman takes position after gunmen attacked the Bethel Memorial Methodist Church in Quetta, Pakistan. (Reuters)

It was the first time ISIS claimed an attack on a church in Pakistan, though other Muslim extremist groups have targeted churches in the past.

The deadliest previous attack on a church was in September 2013, when twin suicide bomb blasts killed 85 people in Peshawar. Jundullah, or Army of God, then a little-known militant group, claimed responsibility.

In March 2015, two suicide bombers attacked two churches in the eastern city of Lahore, killing 15 people. The Pakistani Taliban claimed that attack.

Pakistani Christians have been the target of several attacks in recent years, Reuters reported. There are about 2 million Pakistani Christians living in the country.

The Associated Press contributed to this report.