President Donald Trump is breaking with tradition by visiting Poland, an ex-communist country in central Europe, before making a presidential visit to longtime allies Britain, France or Germany.
Moscow has only once before suspended the hotline, which was established in October 2015 to prevent conflict between the different forces operating in Syrian airspace.
Hundreds were arrested, including opposition leader and protest organizer Alexei Navalny, who was seized outside his Moscow residence while heading to the rally in the city center.
NATO has been informed of the Ukrainian Verkhovna Rada's decision to codify Kyiv's course toward entry into the alliance.
Ambassadors of the European Union’s 28 member states have approved the decision to extend sanctions against Crimea for another year.