Russian forces are bombarding the areas around three Ukrainian cities with the Ministry of Defence warning of increased risk of civilian casualties.
Although on the sixth day the invasion’s advance has made little progress over the last 24 hours, Russian artillery fire has stepped up north of the capital Kyiv, around the second-largest city Kharkiv, and Chernihiv.
The Ministry of Defence said the use of heavy artillery in densely populated urban areas greatly increases the risk of civilian casualties.
An intelligence update said Russia had shifted to nighttime operations in an attempt to reduce losses.
It follows Vladimir Putin’s forces failing to gain control of the airspace over Ukraine.
Boris Johnson has flown to Warsaw to meet with Polish Prime Minister Mateusz Morawiecki.
Johnson is expected to discuss the UK’s financial and diplomatic support for central Europe as it faces the prospect of a humanitarian crisis.
The home secretary Priti Patel rejected calls for a full visa waiver for Ukrainians fleeing the conflict with Russia despite the Government facing criticism for not doing enough to support refugees – including from its own ranks.
Following the Prime Minister’s meeting in Poland, he is set to fly to Estonia, where he will meet with leaders in Tallinn before visiting serving troops alongside Nato secretary-general Jens Stoltenberg.