Boris Johnson pledges to send more arms during surprise visit to Kyiv

Johnson has been praised by Zelenskiy, who contrasts the fulfilment of a promise to deliver vital anti-tank weapons to its army with the more timid responses from other Nato member countries such as Germany.

The besieged city of Mariupol, together with the southern city of Mykolaiv, which has faced significant shelling, are major Kremlin targets, the UK Ministry of Defence has said.

With trains not running out of Kramatorsk on Saturday, panicked residents boarded buses or looked for other ways to get out, fearing the kind of unrelenting assaults and occupations by Russian invaders that delivered food shortages, demolished buildings and death to other cities in Ukraine.

In response to the shelling of Kramatorsk, a curfew in the southern port city of Odesa went into effect on Saturday evening until Monday evening.

Several attempts to evacuate 150,000 people still in Mariupol, which has been under constant fire since 24 February, and bring in vital provisions such as food and medicine, have ended in failure after Russian shelling of safe routes. Two UN agencies also called for urgent action to help an estimated 1,000 seafarers stranded in Ukrainian ports and waters with dwindling supplies.