At least one police officer was among those killed in Monday evening’s attack and more than two dozen people of various nationalities were injured, including four Omani first responders,  Royal Oman Police was quoted as saying by CNN.

According to reports, the attack occurred close to Imam Ali mosque.

The attack took place at the Shi’ite mosque during Ashura, the tenth day of the Islamic month of Muharram, which holds particular significance for Shi’ite Muslims, CNN reported.

Police said three perpetrators were identified and killed during the exchange of fire.

Islamic State terror group has claimed responsibility for the attack.

The Indian Embassy in Oman confirmed one national was killed in the deadly shooting incident.

"Following the shooting incident reported in Muscat city on 15 July, Foreign Ministry of Sultanate of Oman has informed that one Indian national has lost his life & another is injured. Embassy offers its sincere condolences & stands ready to offer all assistance to the families," read the statement issued by the Embassy of India in Oman.

Pakistani Embassy in Oman said four of its nationals were killed and 30 others were injured in the attack.

Condemning the incident, Pakistan PM Shehbaz Sharif posted on X:"Deeply saddened by the terrorist attack on Imam Bargah Ali bin Abu Talib in Muscat, Oman, resulting in the loss of precious lives, including 4 Pakistani nationals. My heart goes out to the families of the victims. I have instructed the Pakistan Embassy in Muscat to extend all possible assistance to the injured and visit the hospitals personally. Pakistan stands in solidarity with the Sultanate of Oman & offers full assistance in the investigation."