* Separatists exchange gunfire with police
* Kiev condemns 'act of aggression' by Russia
* White House warns Moscow against military intervention
* U.S. Vice President Biden to visit Kiev
* "We want to join Russia," gunman says
CORRECTED-UPDATE 2-U.S. to seek to block DraftKings, FanDuel fantasy sports merger
WASHINGTON, June 19 The U.S. Federal Trade Commission said on Monday it will seek to stop the merger of DraftKings and FanDuel, because the combined company would control more than 90 percent of the U.S. market for paid daily fantasy sports contests.