ISLAMABAD, Pakistan — Two suicide bombers attacked a church packed with worshipers on Sunday in southwestern Pakistan, killing at least nine people and injuring at least 35 others, several critically, officials said.

The Islamic State, also known as ISIS, claimed responsibility for the attack in Quetta, the capital of the restive Baluchistan Province, in the country’s southwest. The group’s Amaq News Agency posted a statement online Sunday that said attackers had stormed a church in Quetta, but gave no further details.

The assault raised concerns about the security of religious minorities, especially Christians, in a country with a dismal record when it comes to the treatment and protection of religious minorities, analysts say.

Pakistani officials denied that ISIS had an organized presence in the country, however, even though the terrorist group has claimed responsibility for several other attacks in Baluchistan in recent years.