NATO Secretary General Jens Stoltenberg is convening an extraordinary summit of the Alliance on March 24 to discuss Russia's invasion of Ukraine and support for Ukraine.

"I have convened an extraordinary Summit on 24 March at NATO HQ. We will address Russia's invasion of Ukraine, our strong support for Ukraine, and further strengthening NATO's deterrence & defence. At this critical time, North America & Europe must continue to stand together," he wrote on Twitter.