A total of 22 Shiite Iraqis were shot dead by gunmen in Anbar province in western Iraq on Monday, an Interior Ministry source said.
Gunmen stopped a bus travelling from Syria to Nakhib area of the Iraqi province and drove the bus several kilometers away with the 22 male passengers on board, the source told Xinhua on condition of anonymity.
The 22 men were later found dead and the other eight passengers, all of whom women and children, were spared, the source said.
He said security forces are in a hard bid to search for the attackers and so far no one has claimed responsibility for the incident.
Shiites have been a regular target for Sunni insurgents, who are trying to revive the sectarian violence that brought Iraq to the brink of civil war just a few years ago.
Monday's attack came about four months before U.S. troops are scheduled to fully withdraw from Iraq by the end of the year.