Ukraine's President Volodymyr Zelenskiy said he believes the next 24 hours will be a crucial period for Ukraine as fighting continues across the country.
Zelenskiy told this to UK Prime Minister Boris Johnson during a phone call on Sunday.
During the call, Johnson praised Zelenskiy's leadership since Russia's invasion, according to a UK government spokesperson.
Johnson added the UK would do all it can to make sure defensive aid from the UK and its allies reaches Ukraine.