Russia has said it took action in Crimea after a request for intervention from deposed Ukrainian leader Viktor Yanukovych.
Addressing the UN's Security Council, Russia's representative, Vitaly Churkin, brandished an alleged letter from the former President.
But the assertions are unlikely to ease international pressure as Washington mulls a tough response. On Monday U.S President Obama, outlined some of the punitive measures on the table:
"We are examining a whole series of steps: economic, diplomatic that would isolate Russia and would have a negative impact on Russia's economy and status in the world"
The EU's foreign policy chief, Catherine Ashton, has said a raft of economic and diplomatic actions could be taken:
"Without question, this is in breach of Russia's international obligations and its commitments. We talked about the potential of suspending bilateral talks on visa matters and the New Agreement, and will consider targeted measures."
The EU's next steps in this crisis will be discussed on Thursday when its leaders are set to meet.
But amongst other issues at stake, Europe's dependency on Russian gas may impact how far the bloc is prepared to sanction Moscow.
Source: EuroNews
