UNITED NATIONS, United States (AFP) - Ukraine's deposed president Viktor Yanukovych has formally asked Moscow to deploy Russian troops to re-establish law and order in his country, Russia told the UN Security Council on Monday.

Russia's ambassador told the third round of emergency talks on the Ukraine crisis in New York in four days that Mr Yanukovych had sent a written request to Russian President Vladimir Putin.

Vitaly Churkin said what he called "radical extremists" had seized power in Ukraine and were threatening the lives and legitimate interests of Russian speakers and of Russia's Black Sea fleet.

Quoting from Mr Yanukovych's letter of which he offered to make photocopies available, Mr Churkin said: "Ukraine is on the brink of a civil war. In the country there is chaos and anarchy.

"Under the influence of Western countries there are open acts of terror and violence. People are being persecuted for language and political reasons.

"So in this regard I would call on the president of Russia, Mr Putin, asking him to use the armed forces of the Russian Federation to establish legitimacy, peace, law and order, stability and defending the people of Ukraine," he read.