Turkey's military said the land offensive had fighter aircraft in support. Turkish TV said 3,000 to 10,000 soldiers had entered Iraq, though Iraq's foreign minister denied it was a major operation, saying only a few hundred troops were involved.

Turkish tanks move near the southeastern Turkish town of Silopi, near the Iraqi border on Friday, hunting for Kurdistan Workers Party guerillas. (Reuters)

The European Union repeated its call for Turkey, which is seeking EU membership, to refrain from any disproportionate military action. Britain urged Ankara to leave Iraqi territory as early as possible and Washington also raised concerns.

"The Turkish Armed Forces, which attach great importance to Iraq's territorial integrity and stability, will return home in the shortest time possible after its goals have been achieved," the general staff said in a statement posted on its Web site.

The military source based in southeast Turkey said: "Thousands of troops have crossed the border and thousands more are waiting at the border to join them if necessary."

A PKK spokesman in northern Iraq said rebels were battling the Turkish troops.

"There are severe clashes. Two Turkish soldiers have been killed and eight wounded. There are no PKK casualties," Ahmed Danees, head of foreign relations for the PKK, said by satellite phone from an undisclosed location.

Iraq's foreign minister played down the operation.