Turkey carried out a series of airstrikes in Iraq and Syria Tuesday that reportedly killed up to 20 U.S.-backed Kurdish fighters. U.S. officials say they are « deeply concerned » about the Turkish airstrikes. Two U.S.-backed Kurdish groups, the YPG in Syria and the Peshmerga in Iraq, say the airstrikes hit their camps and killed their fighters. The YPG says the airstrikes also hit a radio station, media center and communication facilities. Turkey says the airstrikes were targeting camps of the Kurdistan Workers’ Party, known as the PKK, which Turkey claims is a terrorist group.