Egypt's foreign affairs ministry condemned a suicide bombing that killed 15 people on Thursday inside a mosque in Abha, a city in south-west Saudi Arabia.

A statement issued by ministry spokesperson Ahmed Abouzid on Thursday stressed the importance of "standing together" to face terrorism on a regional and international level.

The statement offered condolences to the people and government of Saudi Arabia.

Also, Arab League head Nabil El-Araby condemned the attack, expressing solidarity with the victims' families, Saudi people and the government. 

The Islamic State militant group claimed responsibility for the attack.

The group controls large swathes of territory in Syria and Iraq and has been behind a string of attacks that have hit the region.

The mosque in Abha was part of the local headquarters for a state security unit known as the Special Emergency Force, Reuters reported.

Reuters added that 12 of the victims were members of the force, while three were workers in the compound.

They were praying when the bomb detonated.

In May, two suicide bomb attacks in Saudi Arabia killed over 20 people, with the Islamic State group claiming responsibility for both.