Turkish troops have crossed into northern Iraq for a ground operation against separatist Kurdish rebels, the military confirmed Friday.

The mission marks a dramatic escalation in the country's conflict with the militants. It is the first confirmed ground operation by Turkish troops since the Iraq war that brought down Saddam Hussein, reports The Associated Press.

On Thursday, in preparation for the ground incursion, Turkish warplanes and artillery bombed suspected rebel targets in Iraq.

Turkey, aided by U.S. intelligence, has carried out air raids against the Kurdistan Workers Party, or PKK, since December.

The military has also engaged in so-called "hot pursuits," in which small units enter Iraq for a few hours to carry out a specific mission.

Members of the PKK are fighting for independence in Turkey's mainly Kurdish southeast. Militants within the organization have carried out attacks on Turkey via bases in northern Iraq.

"The Turkish Armed Forces, which values Iraq's territorial integrity and its stability, will return as soon as planned goals are achieved," the Turkish military said on its website. "The executed operation will prevent the region from being a permanent and safe base for the terrorists and will contribute to Iraq's stability and internal peace."

A military officer of the U.S.-led coalition in Iraq told AP, on condition of anonymity, that several hundred Turkish soldiers had crossed the border.

Turkish television said 10,000 troops were involved in the mission.

Warplanes were also being used to aid ground troops, reported the state-run Anatolia agency.

The scope or size of the mission was not immediately clear although CNN-Turk television quoted Turkish security officials who said the operation was expected to last two weeks.

The mission was reportedly concentrated in the Hakurk region, south of the Turkish border town of Cukurca.

PKK spokesman Ahmad Danas told AP that two Turkish soldiers had been killed and eight wounded in the clashes but there was no way to independently verify the claims.

Meanwhile, the U.S. military said Friday that they had been assured that Turkey would do everything possible to avoid "collateral damage" to innocent civilians.

"Multi-National Forces-Iraq is aware Turkish ground forces have entered into northern Iraq, for what we understand is an operation of limited duration to specifically target PKK terrorists in that region," Rear Adm. Gregory Smith, a U.S. spokesman in Iraq, said in a statement.

"The United States continues to support Turkey's right to defend itself from the terrorist activities of the PKK and has encouraged Turkey to use all available means, to include diplomacy and close coordination with the Government of Iraq to ultimately resolve this issue."

The European Commission, the administrative body of the European Union, urged Turkey to act with restraint.

"Turkey should refrain from taking any disproportionate military action and respect human rights and the rule of law," commission spokeswoman Krisztina Nagy said.

"The EU understands Turkey's need to protect its population from terrorism," she added. "We encourage Turkey to continue to pursue dialogue with international partners."

Since 1984, as many as 40,000 people have died as a result of the ongoing conflict.

With files from The Associated Press