Four Pakistani nationals and a police officer have been killed and 30 others wounded by gunfire at a mosque in Oman, Omani and Pakistani officials have said, in a rare breach of security in one of the most stable countries in the Middle East.

Omani state media reported on Tuesday that three perpetrators of the attack were killed.

Pakistan's Foreign Ministry said on Tuesday the attack took place in the Ali bin Abi Talib mosque, a Shia mosque in Oman, known locally as the Imam Ali mosque.

Describing the incident in the Wadi al-Kabir district of Oman's capital Muscat as a "terrorist" attack, the Pakistani ministry said 30 injured people were in hospital.

Oman's police on Tuesday also reported the death of four people in the incident.

The attack came as Shia Muslims observed Ashura, an annual period of mourning to commemorate the 7th-century death of Hussein, a grandson of the Prophet Muhammad.

"We are heartened that the government of Oman has neutralised the attackers," Pakistan's ministry said.

Pakistani envoy visits hospital

Pakistan's ambassador to Oman was pictured visiting victims of the attack in a hospital, according to a video the embassy posted on X.

The US embassy in Muscat said it was following reports of the incident.

"US citizens should remain vigilant, monitor local news and heed directions of local authorities," it said in a statement.

Oman has maintained its neutrality in the turbulent region and mediated in disputes, including between the United States and Iran.