"Vladimir Putin must not be allowed to win this war in Ukraine. More than that, he must not be allowed to have a face-saving exit from this war," Russian opposition figure Vladimir Kara-Murza said at a press conference in London.

Putin argued that the attack didn't divert Russia from a more important mission — gaining ground in eastern Ukraine.

Western governments and Russia's exiled opposition should begin laying the groundwork for Russia's democratic transition after President Vladimir Putin eventually leaves office, Vladimir Kara-Murza, a Russian opposition politician,