"At 8:30 am (0530 GMT), gunmen riding in a car and carrying automatic weapons killed five policemen guarding a checkpoint, before fleeing," the officer in the provincial capital Ramadi said.
He said the gunmen struck in the desert town of Rutbah, on the main highway leading from Baghdad towards Amman and Damascus.
Last month was the deadliest this year in terms of the number of Iraqis killed in attacks, according to government figures. It was the deadliest since June 2008 for US troops, who are due to withdraw by the end of this year.
A total of 271 Iraqis and 14 US soldiers lost their lives.
Iraq has blamed al Qaeda for the increased death toll, which was up 34 percent on May. But the US military holds Iranian-backed Shiite militias responsible for the deadly attacks on its troops.
Copyright AFP (Agence France-Presse), 2011