By David Shepardson and Costas Pitas WASHINGTON (Reuters) -The United States on Sunday ordered the departure of family members of staff at its embassy in Ukraine, citing the continuing threat of military action from Russia. The U.S. State Department also authorized the voluntary departure of U.S. government employees and said Americans should consider departing immediately. “We have been in consultation with the Ukrainian government about this step and are coordinating with Allied and partner embassies in Kyiv as they determine their posture,” the U.S. Embassy said. Russia has massed troops ne…