MOSCOW. June 19 (Interfax) - Russian planes were in the air when a U.S. fighter downed a plane of the Syrian Air Force, the Russian Defense Ministry said on Monday.
"Planes of the Russian Aerospace Forces were accomplishing missions in the Syrian airspace in that period of time," the ministry said.
"However, the coalition command did not use the dedicated line between the commands of the Al Udeid airbase (Qatar) and the Hmeimim airbase for the purposes of preventing incidents in the Syrian airspace," the ministry said.
"We deem this conduct of the U.S. command to be a witting act of non-fulfillment of their obligations under the Russia-U.S. Memorandum of Understanding on the Prevention of Flight Safety Incidents in Syria dated October 20, 2015," the ministry said.