The Islamic State has claimed responsibility for the suicide attack at a mosque used by the Saudi special forces, which killed 17 security officers in Abha city on Thursday afternoon.
According to state-run TV channel El-Ikhbariya, the attack took place during the time of prayer. Saudi Arabia is treating the incident as a terror attack.
At least 25 people were injured in the blast, it was reported.
The terror group posted a message on social media platforms and said that it attacked the men as they supported the rule of monarchs and and were unjust to those who spoke in favour of the Isis, reported The Guardian.
Reuters reported that the mosque was being used by a state security unit called the Special Emergency Force and all those killed were its members.
A Saudi official told the Associated Press on condition of anonymity that the mosque belongs to the interior ministry emergency services posted in Abha in the southern region of the kingdom.
Middle East Eye reported that the death toll is expected to climb as many have been critically injured.
A highly-place source told MEE that the bomber had disguised himself as a mosque cleaner in order to gain access into the place and in the afternoon, when all security personnel were inside the mosque, the bomber detonated the suicide vest.
— Mohammed K. Alyahya (@7yhy) August 6, 2015
It was, however, not clear if the mosque was part of an interior ministry compound. No group had claimed responsibility for the latest terror attack, BBC reported quoting officials.
Abha, the capital of Asir region, is located in the south-west of the Kingdom, close to the country's border with Yemen, where Saudi Arabia is currently engaged in a war to push back Houthi rebels.
In recent months, the Kingdom of Saudi Arabia has witnessed a spat of suicide attacks carried out by the Islamic State (Isis) terrorists. This is the third suicide attack on a mosque in KSA this year.
An Isis suicide bomber on 22 May, blew himself up at the Imam Ali Mosque in Qatif, during Friday prayers, killing 21 people and wounding more than 100.
Within a week, Isis carried out another bombing on May 29 at Al-Anoud Mosque, where the bomber came dressed as women.Four people were killed in the blast.
The suicide attack comes at a time, when Saudi Arabia has declared a war against Isis supporters in the country. In July, KSA claimed that it foiled an Isis plot to attack seven mosques across the kingdom after it arrested 431 "plotters".
— أخبار السعودية (@SaudiNews50) August 6, 2015