Kyiv is working with allies on security guarantees akin to NATO's mutual protection pledge, Ukraine's president Volodymr Zelensky has said. Officials from Ukraine and allies the U.S., the U.K., France and Germany met in London on Thursday in a week when a peace proposal was produced which outlined an Article 5-like agreement which would be backed by Washington.

President Donald Trump is calling for Ukraine and Russia to meet for “very high level talks,” saying they are “very close to a deal” after productive meetings.

The president’s comments came after he said Crimea “will stay with Russia,” a position backed by the mayor of Kyiv, who conceded that his country may have to give up territory.

Russia said it arrested a man suspected in the murder of a senior military official near Moscow and claimed that a car bomb had been activated remotely from Ukraine.

President Donald Trump said on Thursday he was not happy with Russia's strikes on the Ukrainian capital Kyiv overnight and said without elaborating the U.S. was putting a lot of pressure on Russia to make a deal.