"Crimea was, is and will be an integral part of Ukraine."
That was the statement by Ukraine's interim prime minister on Thursday in response to the Crimean Parliament's vote to bring forward a referendum on March 16th to reunite the autonomous republic with Russia.
The U.S. and EU stood with the Ukrainian government in condemning the move, saying the referendum violates the Ukrainian constitution as well as international law.
The EU at a meeting in Brussels urged Russia to de-escalate the situation.
"Any further steps by the Russian Federation to destabilize the situation in Ukraine would lead to severe and far-reaching consequences for relations between the European Union and its member states on the one hand and the Russian Federation on the other hand, which will include a broad range of economic areas."
The EU also talked of sanctions, including travel bans and asset freezes.
A cancellation of an upcoming EU-Russia summit was also considered.
However, not all EU members are in favor of the proposed sanctions, since they would come at a cost to them as well.
The U.S., has already imposed visa restrictions on Russian officials.
President Barack Obama told his Russian counterpart Vladimir Putin that Russia's violation of Ukraine's territorial integrity had prompted the U.S. to take a number of punitive steps in response.
The White House says that, during an hour-long phone call Thursday, hours after the Crimean vote, Obama called on Putin to hold direct talks with the new government in Ukraine and urged him to find a diplomatic resolution to the situation.
Officials and experts believe that the Ukrainian crisis is no longer one between divided groups within the country, but also a serious issue between the West and Russia.
UK Prime Minister David Cameron compared the situation to World War Two, saying "the slightest miscalculation could see the situation spiral out of control."
Kwon Soa, Arirang News.