Four people, including two Pakistanis, were killed and multiple others wounded in a shooting near a Shiite mosque in the Omani capital Muscat, officials said Tuesday, a rare attack in the otherwise stable Gulf sultanate.

Shiites make up a small minority of Oman's overwhelmingly Muslim population. Most Omanis follow the Sunni or Ibadi branches of the faith.

Monday's mosque attack, which has yet to be claimed, came as Shiites this week mark Ashura, an annual day of mourning that commemorates the seventh-century death in battle of Imam Hussein, regarded by Shiites as the rightful successor to the Prophet Mohammed.

"The Royal Oman Police have responded to a shooting incident that occurred in the vicinity of a mosque in the Al-Wadi Al-Kabir area" of the capital, police said in a statement.

The force gave an initial toll of four killed and "several" wounded.

Two Pakistanis were among those killed in the attack on the Imam Bargah Ali bin Abu Talib mosque, the foreign ministry in Islamabad said, adding that Omani authorities have "neutralised" the gunmen.

"Pakistan strongly condemns the dastardly terrorist attack," it said in a statement.

"We are heartened that the government of Oman has neutralised the attackers."

There were also Pakistanis among the wounded, the embassy in Muscat said, adding that the number had yet to be confirmed.

Pakistani ambassador Imran Ali visited some of the wounded in hospital, the embassy posted on social media platform X.

In a video message, Ali urged Pakistani residents to cooperate with Omani authorities and avoid the area around the mosque which was hit.

"I have visited three or four hospitals. By the grace of God, all those injured are safe," Ali said.

"We are in touch with Omani authorities as well as hospitals. Our officers are on standby for emergency blood donations in the embassy," he added, saying a hotline has been set up to assist the wounded and their relatives.

The US embassy in Muscat issued a security alert following the shooting and cancelled all visa appointments Tuesday.

"US citizens should remain vigilant, monitor local news and heed directions of local authorities," the embassy posted on X.

Footage verified by AFP shows people fleeing the Imam Ali Mosque, its minaret visible, as gunshots ring out.

A voice can be heard saying "oh God" and repeating "oh Hussein".

Ashura 

Police said "all necessary security measures and procedures have been taken to handle the situation" following the attack.

"The authorities are continuing to gather evidence and conduct investigations to uncover the circumstances surrounding the incident," police added on X.

The area was cordoned off on Tuesday, with journalists unable to access the mosque, an AFP photographer reported.

Oman has a population of over four million, more than 40 percent of whom are expatriate workers, according to government figures.

The sultanate has repeatedly played the role of a mediator in regional conflicts, especially the war in Yemen between Iran-backed Huthi rebels and the internationally recognised government propped up by Saudi Arabia.

While several attacks on Shiite mosques have roiled the Gulf in recent years, Tuesday's attack is a first for Oman.

A 2015 suicide attack on a Shiite mosque in Kuwait killed at least 27 worshippers and wounded more than 200. It was claimed by the Sunni extremists of the Islamic State group.

That same year, Saudi Arabia saw two attacks on Shiite mosques in the space of a week. The twin assaults killed at least 25 people and were again claimed by IS, which regards Shiites as heretics.

In 2005, a former teacher opened fire inside a government building in Muscat, killing two people and wounding several others, before shooting himself.