Open this photo in gallery: A Ukrainian serviceman from Azov brigade known by call sign Ray, 20, carries a shell for the OTO Melara Mod 56 howitzer on the frontline in Kreminna direction, Donetsk region, Ukraine, on April 11.Alex Babenko/The Associated Press The U.S. has lifted a ban on providing American weapons and training to a controversial Ukrainian military unit that was key to the defence of the major port city of Mariupol, the State Department said on Tuesday. The Azov Brigade is among Ukraine’s most effective and popular fighting units – but has been dogged by its origins as...