President Tayyip Erdogan said on Sunday that Turkey had begun operations in Iraq's Sinjar region, an area where it has threatened a military incursion, two days after sources said Kurdish PKK militants would withdraw from the area.

"We said we would go into Sinjar. Now operations have begun there. The fight is internal and external," Mr Erdogan told a crowd in the Black Sea province of Trabzon, without elaborating on what operations he was referring to.

Iraq's Joint Operations Command denied that any foreign forces had crossed the border into Iraq.

"The operations command confirmed that the situation in Nineveh, Sinjar and the border areas was under the control of Iraqi security forces and there is no reason for troops to cross the Iraqi border into those areas," it said in a statement.

Sources in Sinjar said there was no unusual military activity in the area on Sunday.