Turkish troops, backed by the air force, have killed 22 Kurdish rebels in an operation in southeast Turkey in the last five days, military headquarters said on Tuesday. It said a senior Kurdistan Workers Party (PKK) militant was among those killed in the operation. The military launched the operation on Friday after spotting a group of PKK militants preparing for an attack in the mountains of Sirnak province near the Iraqi border. The General Staff said on its website the air force launched the operation and were then backed up by attack helicopters and artillery fire. The figures could not be independently confirmed. Sabah newspaper had reported that F-16 fighter jets had been bombarding the rebels along the border during the operation in which 500 soldiers took part. PKK shelters, weapons and ammunition were destroyed in the operation, the military statement said. The rebels regularly enter Turkey from the mountains of northern Iraq, where several thousand PKK militants are based. This year the Turkish military has launched a series of raids against the group in northern Iraq. The PKK, regarded as a terrorist group by Turkey, the United States and European Union, took up arms against the Turkish state in 1984 with the aim of setting up an ethnic homeland in southeast Turkey. Some 40,000 people have been killed in the conflict.