SULAIMANIYAH, Iraq — Turkish helicopters swooped into Iraqi territory Tuesday, Iraqi officials said, firing on villages in renewed pressure to dislodge Turkish Kurd guerrillas from bases in northern Iraq used to stage cross-border raids.

The helicopter attack was the first major Turkish action against the rebels since Turkish Prime Minister Recep Tayyip Erdogan met with President Bush in Washington on Nov. 5. Turkey has demanded that the U.S. and Iraq crack down on guerrillas operating from Iraqi territory and has massed tens of thousands of soldiers along the border with Iraq.

The United States and Iraq have urged Turkey, a NATO member, to avoid a large-scale attack on rebel bases in northern Iraq, fearing such an operation would destabilize what has been the calmest region in the country.

A spokesman for the Iraqi Kurd regional administration, Jamal Abdullah, denied the helicopter attack report but said two Turkish warplanes dropped flares Monday in the mountains near the Iraqi town of Zakhu.

But Col. Hussein Tamir, an Iraqi army officer who supervises border guards, said the Turkish helicopters opened fire before dawn on abandoned villages northeast of Zakhu, an Iraqi Kurd town near the border with Turkey. There were no casualties, he said.

On Tuesday, the U.S. military said American and Iraqi troops killed 15 suspected al-Qaida in Iraq militants in a daylong battle the day before in Adwaniyah, about 12 miles south of Baghdad.

During the battle, American F-16 fighter jets dropped two 500-pound bombs on insurgent positions, the military said. It was unclear whether the 15 victims died in the gunbattle, or as a result of the U.S. bombing.

Elsewhere, at least 16 people were killed or found dead across the country Tuesday, according to police reports. Most of the deaths occurred outside of Baghdad.

In Washington, a new report said the economic costs of the wars in Iraq and Afghanistan are estimated to total $1.6 trillion — roughly double the amount the White House has requested thus far.

The report by Democrats on Congress' Joint Economic Committee attempted to put a price tag on the two conflicts, including "hidden" costs such as interest payments on the money borrowed to pay for the wars, lost investment, the expense of long-term health care for injured veterans and the cost of oil market disruptions.