Britain has asked for an emergency meeting of the U.N. Security Council on Ukraine.
Britain's U.N. Mission said Thursday the time of the meeting has not been set.
The request follows Wednesday's downing of a Ukrainian air force fighter and Thursday's downing of a Malaysia Airlines passenger plane carrying 295 people over eastern Ukraine.
Ukraine's U.N. Ambassador Yuriy Sergeyev tweeted after Thursday's crash in a rebel-controlled area that "Ukraine will present the evidence of Russian military involvement into the Boeing crash. This crime should be fully investigated."