Nine people were killed, including three attackers, and more than two dozen others were injured in an assault on a mosque in Oman late on Monday, law enforcement said. Four Pakistanis , an Indian and a police officer were among those killed in the gun attack. The Oman police said 28 people of various nationalities were wounded, including security personnel. Police have not said whether they have identified a motive for the attack or if they had made any arrests. Pakistan's foreign ministry said the attack took place at the Ali bin Abi Talib mosque. The attack came as Shi'ite Muslims observed Ashura, an annual period of mourning to commemorate the 7th century death of Hussein, a grandson of the Prophet Muhammad.