Exit polling in the Crimean referendum are suggesting well over 95-percent have voted in favor of becoming part of Russia and seceeding from Ukraine.

Many pro-Russia voters are already celebrating in the streets.

The region's pro-Russia leader has already announced he will apply to join Russia later on this Monday.

Russian president Vladmir Putin is on-record saying he'll support the outcome of the referendum, saying it doesn't breach any international law.

However, the European Union and the United States have condemned the ballot, saying it has been conducted under military intimidation from Moscow and is therefore illegal.

White House Senior Adviser Dan Pfeiffer.

"This referendum is in violation of international law, the United States is not going to recognise the results of that referendum and we are working with our partners around the world, the Europeans in particular to marshal forces against the Russians to put pressure on them in the form of sanctions."

A US-sponsored draft resolution in the UN Security Council to nullify the outcome of the Crimean vote has been vetoed by Russia.

EU ministers are set to meet later on this Monday to consider imposing sanctions on Russia.

In Crimea, despite the overwhelming support from the ethnic Russian community for the sessesion, the ethnic Tatar population, which makes up 12-percent of the population in Crimea, have largely boycotted the referendum.

Tensions have been flaring up as Ukrainian troops have blocked roads after Russian troops moved in to try to seize a local gas distribution centre.