Boris Johnson has pledged that the UK and its allies will respond “decisively” to Russia’s attack on Ukraine as he prepared to address the nation amid pressure to announce further sanctions.

The prime minister also condemned Vladimir Putin, saying Russia’s president had “chosen a path of bloodshed and destruction” that was a “catastrophe for our continent”.

Following a meeting of the government’s emergency Cobra committee at 7:30am on Thursday morning, Johnson is expected to give an address to the nation at around 11am, followed by a call with G7 leaders in the afternoon and a statement in the House of Commons at 5pm

It came as Ukraine’s president declared martial law, while Russia’s military said it had targeted Ukrainian airbases and other military assets and had not targeted populated areas.

A Downing Street spokesperson said Johnson chaired a Cobra committee meeting at 7.30am this morning to discuss the response to the “horrific attacks”.