KABUL -- Afghan police, troops and intelligence agents backed by NATO forces killed 18 militants in a joint operation in Afghanistan's restive southern province of Helmand, the Interior Ministry said Tuesday. Six militants also were arrested during the operation in Helmand's Sangin district, the ministry said. It was one of a string of operations Monday that officials said left at least 30 insurgents dead in southern and eastern Afghanistan. NATO did not provide immediate comment. In the Shah Wali Kot district neighboring Kandahar province, one Afghan man was killed and a woman wounded after insurgents attacked a house Monday evening, deputy provincial police chief Fazel Ahmad Sherzad said. Sherzad said the man was targeted because of dealings with Afghan government officials, and that three insurgents were killed in fighting that occurred after the house was attacked. Thousands of U.S., NATO and Afghan forces are ramping up pressure on Kandahar ��" the birthplace of the former Taliban regime, whose insurgents have been trying to destabilize the government of President Hamid Karzai.