BBC journalists Clive Myrie and Lyse Doucet put on flak jackets after their live broadcast from Ukraine was interrupted by a warning siren.

       The pair have been reporting on the Russian invasion from a rooftop opposite St Michael’s Cathedral in the capital of Kiev.

       Russian president Vladimir Putin has launched a military operation in eastern Ukraine, with the president of the country, Volodymyr Zelensky, declaring martial law.

       During a broadcast shortly after midday on Thursday, Doucet continued to address the camera while a siren was heard in the background.

       After the broadcast cut to the BBC studio in London’s Broadcasting House, the pair reappeared on screen wearing blue flak jackets, worn as protection against bullets and shrapnel.

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       Myrie said: “We heard the air raid sirens, we have put on our flak jackets.

       “One wonders what the people of this city and indeed right across this country are now thinking.

       “They prayed for peace and with all the diplomacy over the last few weeks and months, they hoped that would be the case.

       “Now we are in a major conflict.”

       Ukrainian president Volodymyr Zelensky (Peter Nicholls/PA)

       (PA Wire)

       Doucet, the BBC’s chief international correspondent, replied: “The siren has spoken.

       “The siren spoke live in our broadcast and that siren, not only did it strike fear in the hearts of all the Ukrainians being told to stay at home today and some still bravely went to work.

       “A siren telling them: ‘Be careful, something even more dangerous could come’.

       “But that siren was also heard across the UK and around the world.”

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       Prime Minister Boris Johnson described the Russian invasion as a “catastrophe for our continent”.

       Around 40 people have died in Ukraine so far, according to an adviser to the country’s president.