ISTANBUL, Dec 9 (Reuters) - Three Turkish soldiers were killed in an attack by Kurdish militants during cross-border operations in northern Iraq on Thursday, the Turkish Defence Ministry said, adding six of the militants were "neutralised". "Targets identified in the region were struck in an air operation and six terrorists were neutralised according to initial indications. Operations in the region are continuing," the ministry said. "Neutralised" is commonly used to mean killed. Turkey"s operations in Iraq target the Kurdistan Workers Party (PKK) militant group, which has bases there and which is designated a terrorist group by Turkey, the United States and European Union. The group launched an insurgency in southeast Turkey in 1984 in which more than 40,000 people have been killed.