Prime Minister David Cameron said:
Britain views the developments in the Ukraine with growing concern.
This afternoon, in view of the seriousness of events unfolding there today, and the Russian Parliament’s decision to authorise Russian military intervention, the United Kingdom has called an emergency meeting of the UN Security Council.
There can be no excuse for outside military intervention in Ukraine - a point I made to President Putin when we spoke yesterday.
Everyone must think carefully about their actions and work to lower, not escalate tensions. The world is watching.