CUKURCA, Turkey – A Turkish helicopter crashed in Iraq and eight soldiers were killed during a cross-border ground operation against Kurdish rebels, who planted booby traps on the bodies of their slain comrades, Turkey’s military said Sunday.

The guerrillas said they shot down a Turkish military helicopter near the Turkish-Iraqi border.

Turkey’s military said technicians were inspecting the wreck to determine why the helicopter crashed near the border. It was not clear if any of the reported troop casualties were on board. Their deaths bring the Turkish toll since the start of the incursion Thursday to 15, the military said on its Web site.

Thirty-three rebels were killed in Sunday’s fighting, bringing the rebel death toll since Thursday to 112, according to the armed forces.

The incursion is the first confirmed Turkish military ground operation in Iraq since the U.S.-led invasion that toppled Saddam Hussein in 2003.

The rebels of the Kurdistan Workers’ Party, or PKK, are fighting for autonomy in predominantly Kurdish southeastern Turkey and have carried out attacks on Turkish targets from bases in the semiautonomous Kurdish region of northern Iraq. The conflict started in 1984 and has claimed as many as 40,000 lives.

Turkey has assured that the operation would be limited to attacks on rebels. The United States and European Union consider the PKK a terrorist group.

“It is only an operation geared to cleansing the terrorist camps,” Turkey’s prime minister, Recep Tayyip Erdogan, said Sunday in an address to the youth branch of his ruling party. “Our Iraqi brothers, friends and civilians should know that they will never be targeted by the armed forces.”

U.S. Defense Secretary Robert Gates said Sunday while visiting Australia that it would take a broader approach to erode PKK support in northern Iraq.

“After a certain point people become inured to military attacks,” he said, “and if you don’t blend them with these kinds of nonmilitary initiatives, then at a certain point the military efforts become less and less effective.”