Turkish F-16 jets buzzed over the small Turkish hilltop town of Cukurca on Sunday as elite commandos chased Kurdish guerrillas across the border in northern Iraq in a major ground operation. Armored personnel carriers transported troops in full combat gear and four long-range guns were positioned at the edge of a helicopter base in the border town, where at least four attack helicopter gunships were stationed. The base in Cukurca is one of the main support centers for the Turkish operation across the border, which began Thursday. The Turkish military said it attacked rebel hide-outs on Saturday with fighter jets, helicopter gunships and artillery. The hide-outs had ammunition and explosives inside, a military statement said. Kurdish rebels said they shot down a Turkish Cobra attack helicopter during Saturday's fighting near the village of Hore, close the Turkish border, the pro-Kurdish Firat news agency reported. There was no confirmation from Turkey and no way to verify the claim independently. Earlier, the Turkish military said seven soldiers and at least 79 rebels have been killed in the operation since Thursday. The rebels of the Kurdistan Workers' Party, or PKK, said they have killed 15 Turkish troops. The incursion is the first confirmed Turkish military ground operation in Iraq since the US-led invasion that toppled Saddam Hussein in 2003. The rebels 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 the US-backed Iraqi government that the operation would be limited to attacks on rebels. The United States and European Union consider the PKK a terrorist group. US Defense Secretary Robert Gates said Sunday while visiting Australia that it will take a broader approach to erode support for the PKK 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." On Saturday, Iraq's government also criticized the offensive, saying military force will not solve the Kurdish problem. "We know the threats that Turkey is facing but military operations will not solve the PKK problem. Turkey has resorted to military options, but this never resulted in a good thing," Iraqi government spokesman Ali al-Dabbagh said. Massoud Barzani, head of the regional Kurdish administration in northern Iraq, warned Turkey it will face large-scale resistance if it targets civilians in its ground incursion. The Iraqi government said Saturday that fewer than 1,000 Turkish troops had crossed the frontier. Turkish media reports have put the number in the thousands.