Units of Afghan national police during series of operations across the country over the past 24 hours have killed 12 Taliban militants, Interior Ministry said in a statement released here on Monday.The operations, according to the statement were conducted in Nangarhar, Kandahar, Uruzgan, Maidan Wardak, Logar, Farah and Helmand provinces which have also left eight more militants wounded and four others arrested.However, it did not say if there were any casualties on police. Taliban militants fighting the government have yet to make comment.