Omani police said it killed three gunmen behind the attack and that authorities “concluded the procedures for dealing with the shooting,” though the statement did not disclose the attackers’ identity.

Qatar has issued a statement offering support and condolences for Oman following Monday’s rare shooting incident in Muscat that killed six people and for which ISIL has claimed responsibility.

In a statement on Wednesday, Qatar’s foreign ministry praised its Gulf neighbour while expressing its condolences to the families of the victims’ families.

“The Ministry of Foreign Affairs affirms Qatar’s full support for all measures taken by the Sultanate of Oman to maintain its security and stability. The Ministry expresses the State of Qatar’s condolences to the victims’ families and wishes the wounded a speedy recovery,” the statement said.

The shocking incident occurred in Wadi Kabir, a district in the east of Muscat, during a large religious gathering for Shia Muslims that were commemorating the day of Ashura. 

During Ashura, Muslims commemorate the seventh-century battlefield martyrdom of Imam Hussein, Prophet Muhammad’s grandson.

Muslims at the gathering in Oman fled the area near the Imam Ali Mosque upon hearing gunfire by the assailants. The shooters killed six people including four Pakistani nationals, an Indian national, and a policeman.

Thirty others have been injured by gunshots or in a stampede that occurred while desperately fleeing the scene. ISIL then claimed responsibility for the attack, confirming that its members shot worshippers at the mosque.