NEW : Iran and Turkey long have targeted Kurdish separatist rebels operating in northern Iraq . U.S. military : David Perkins who killed 2 Iraq troops , wounded 3 was Iraqi soldier . Iraqi officials say shooter was soldier-in-training who opened fire at a training facility . Shootings underscore the dangers for U.S. troops and Iraqi security forces in U.S. . Iranian forces attacked Kurdish village in Mosul ; 3 civilians killed in Iraq .
NEW : U.S. military : David Perkins who killed 2 Iraq troops , wounded 3 was Iraqi soldier . Iraqi officials say shooter was soldier-in-training who opened fire at a training facility . Shootings underscore the dangers for U.S. troops and Iraqi security forces in U.S. . Iranian forces attacked Kurdish village in Mosul ; 3 civilians killed in Iraq .