WASHINGTON / ISTANBUL  

Two Pakistani nationals were among at least four people killed in a shooting near a mosque in Oman early Tuesday.

Several people were also wounded by gunfire in the vicinity of the mosque in the Wadi al-Kabir area of the capital Muscat, police said.

An investigation is underway.

Pakistan Foreign Ministry in Islamabad said two of the slain were its citizens.

Mumtaz Baloch, spokeswoman of the ministry, said 30 others were injured in the, what she called, "terrorist attack" on an Imam Bargah in Oman.

"Our deepest condolences to the families of the victims," said Baloch, adding that Pakistani ambassador Imran Ali had visited the injured Pakistanis in hospitals.

The diplomatic mission is in contact with Omani authorities and Pakistani community, she added.

Following the shooting, the US Embassy in Muscat had issued a security alert saying: "U.S. citizens should remain vigilant, monitor local news and heed the directions of local authorities."