Crimea's parliament on Thursday voted to join Russia and decided to hold a referendum within the next ten days even as the European Union-backed Ukrainian government declared the referendum illegal and opened a criminal investigation against Crimean prime minister Sergei Askyonov, who was appointed by the region's parliament last week.
Ukraine's new prime minister Arseny Yatseniuk said after meeting EU leaders that Ukraine's armed forces would act if Russian military intervention escalated any further into Ukrainian territory.
"We are ready to protect our country," he said, although Ukraine is no match for superpower Russia.
Meanwhile, in a show of support to EU, the US Navy announced a guided-missile destroyer, the USS Truxton, was heading to the Black Sea, but said it was a long-planned training exercise and not a show of force.
Crimea's move to part ways with the anti-Russian government in Kiev is expected to escalate the crisis in Ukraine as Crimea is majority inhabited by ethnic Russians.
The sudden moves by Crimea, the Ukrainian Black Sea peninsula, has unnerved European Union leaders who held an emergency summit to look for ways to pressure Russia to back down and accept mediation.
The West believes that Crimea's decision could not have been made without Putin's approval since Crimea is home to Russia's Black Sea Fleet stationed in Sevastopol.
The US department of state, meanwhile, released a fact sheet that dismissed President Vladimir Putin's comments of European intervention to foment the crisis in Ukraine as "false claims", which prompted Russian criticism of US cynicism and double standards and a "primitive distortion of reality."
On the other hand, Obama ordered the freezing of US assets of Russians blacklisted by the US and impose a ban on Russians travelling to the United States, for what he called "threatening the sovereignty and territorial integrity of Ukraine",
The blacklist, however, does not contain the name of Russian President Vladimir Putin.
The crisis in Ukraine began in November when violent mobs turned against President Viktor Yanukovich for allegedly breaking a trade deal with the European Union and forced him out on 22 February with EU backing, thus ensuring that Ukraine accepted a $15 billion EU aid.
Moscow denounced the events as an illegitimate coup and refused to recognise the new Ukrainian authorities. Russia had, last week, stationed troops near Ukraine border, but later decided to withdraw forces saying intervention was not needed under existing circumstances.
Now that the Crimean parliament has voted unanimously "to enter into the Russian Federation with the rights of a subject of the Russian Federation," the EU and the US have reason to worry.
The vice premier of Crimea said a referendum on the status would take place on 16 March. All state property would be "nationalised", the Russian rouble adopted and Ukrainian troops treated as occupiers and forced to surrender or leave, he said.
A Crimean parliament official said
The two million voters in the Crimea region will be asked two questions: should Crimea be part of the Russian Federation and should Crimea return to an earlier constitution that gave the region more autonomy?
Russia said it would make it easier to give passports to native Russian speakers who have lived in Russia or the former Soviet Union.
Crimean forces have, meanwhile, stopped a 35-member military observers from the pan-European Organisation for Security and Cooperation from entering Crimea, Poland's defence minister said.