A treaty signed in 1994 by the US and Britain could pull both countries into a war to protect Ukraine if President Putin’s troops cross into the country.
Bill Clinton, John Major, Boris Yeltsin and Leonid Kuchma – the then-rulers of the USA, UK, Russia and Ukraine – agreed to the The Budapest Memorandum as part of the denuclearization of former Soviet republics after the dissolution of the Soviet Union.
Technically it means that if Russia has invaded Ukraine then it would be difficult for the US and Britain to avoid going to war.
The revelation comes as reports suggest the Kremlin was moving up to 2,000 troops across the Black Sea from Novorossiysk to their fleet base at Sevastopol.
At least 20 men wearing the uniform of the Russian fleet and carrying automatic rifles surrounded a Ukrainian border guard post in a standoff near the port yesterday.
Last night it was still unclear the exact scale of Russian boots on the ground in Crimea or the identity of gunmen who have taken over airports in Simferopol and Sevastopol – though reports suggest they are Russian marines or Moscow- controlled militias.
The action came as President Obama delivered blunt warnings to Moscow.
‘We are now deeply concerned by reports of military movements taken by the Russian Federation inside of Ukraine,’ he told reporters at the White House.
‘Any violation of Ukraine’s sovereignty and territorial integrity would be deeply destabilizing,’ he said in a brief appearance.
‘The United States will stand with the international community in affirming that there will be costs for any military intervention in Ukraine.’
U.S. officials also said the President could scrap plans to attend an international summit in Russia and take negotiations on deepening trade ties with the country off the table in response to Russian involvement in the Ukraine.
Defense Secretary Chuck Hagel added: “This could be a very dangerous situation if this continues in a provocative way.”
Asked about options in a CBS News interview, he said that “We’re trying to deal with a diplomatic focus, that’s the appropriate, responsible approach.”