President Volodymyr Zelensky told Boris Johnson in a phone call on Sunday evening that the next 24 hours would a “crucial period” for Ukraine.
The British prime minister promised Mr Zelensky he will do “all he could” to ensure further military aid reaches Ukrainian forces, who were involved in further heavy fighting at the weekend.
Just hours earlier, Vladimir Putin placed Russia’s nuclear deterrence forces on high alert, citing aggressive statements by Nato leaders and economic sanctions against Moscow over its invasion of Ukraine.
The aggressive move comes as a Ukrainian delegation is due to meet the Russians “without precondition” on Monday on the border with Belarus, although Mr Zelensky has indicated he sees little prospect of any meaningful dialogue.
Meanwhile, the EU announced on Sunday that they would close their airspace to Russian planes, fund arms supplies to Ukraine and ban pro-Kremlin media.
The bloc also said it was ready to supply combat jets to the Ukrainian armed forces, the head of European diplomacy Josep Borell said.
