Sochi Mayor Anatoliy Pakhomov handed the Olympic flag to Pyeongchang Mayor Lee Sok-ra during the closing ceremony for the Sochi 2014 Winter Olympics.
South Korean city of Pyeongchang will host the Winter Olympics in 2018.
More top news
Among those murdered was Keith Palmer, an unarmed constable who "did his job and never wanted any fuss."
Top temperature 14 Celsius (57 F).
The Prime Minister will say Moscow's brazen flouting of international law represents a threat to the basis of democracy across Europe.