Six people, including a policeman, have been killed and 28 others injured in a rare shooting attack near a Shia Muslim mosque in Oman’s capital, Muscat, police say.

The three attackers were also killed by security forces during the incident in the al-Wadi al-Kabir area on Monday night, according to a statement.

Police gave no details about the identities of the victims and gunmen, or the motive. But Pakistan said four Pakistanis were among those killed in a “terrorist attack” on the Imam Ali Mosque. India also said one of its citizens was killed.

The Sunni Muslim jihadist group Islamic State (IS) says three of its members were involved in the attack.