Three Turkish soldiers were killed and eight wounded yesterday when their vehicle hit a land mine suspected of being planted by Kurdish rebels in Turkey's southeast, security sources said. The soldiers were in Hakkari, a remote province bordering Iran and Iraq. The military has launched a sweeping operation along the full stretch of the Iraqi border in Hakkari and the neighboring province of Sirnak, a military official said. "A large-scale operation with between 3,000 and 4,000 troops backed by air support is continuing," he said. Rebels from the separatist Kurdistan Workers Party (PKK) have stepped up their attacks on military and strategic targets after calling off their unilateral cease-fire in June 2004.In the last week, the PKK claimed responsibility for two separate explosions that hit railway lines in eastern Turkey. Six security guards died in the first attack on a postal train. "PKK militants are bringing C-4 plastic explosives and other materials across the Iraqi border," the official said. "They are engaging in the low-risk tactic of detonating bombs and mines by remote control in attacks on military vehicles in the region."