Russia-Nato relations hit a new low on Tuesday over a spy row and military exercises due to kick off in Georgia, as Tbilisi accused Moscow of staging a military coup at one of its bases.
Russian foreign minister Sergei Lavrov cancelled his planned meeting of the Nato-Russia Council on 18 May and the government expelled two Canadian diplomats working at the north Atlantic alliance's information bureau in Moscow.
The move came as tit-for-tat to Nato's expulsion of two Brussels-based Russian diplomats accused of spying. One of the two men, administration director Vasily Chizhov, is also the son of Russia's ambassador to the EU, Vladimir Chizhov.
Russia had already pulled out of a planned meeting among senior military staff on 7 May in protest at the military exercises due to start today in Georgia.
Moscow has called the simulations "muscle flexing" and insisted that Nato to cancel them, saying they were taking place "where there was recently a war", alluding to the Russian invasion of Georgia after Tbilisi launched an attack against separatist forces in South Ossetia.
In a parallel development, the Georgian government on Tuesday stopped an attempted army mutiny that they say was staged by Russia and designed to disrupt the Nato exercises. A former Georgian special forces commander and a tank battalion commander were arrested.
President Mikhail Saakashvili called on Russia to stop its "provocative maneuvers" in Georgia.
A spokesman for the Interior Ministry said that initial evidence and secret recordings show that the mutineers had Russian backing. The investigation was ongoing, he added.
Moscow denied involvement in the events and dismissed the accusations as "ridiculous."
The US reacted cautiously, calling the foiled mutiny plot an "isolated incident" that the Pentagon was still assessing.
Defense Department spokesman Bryan Whitman avoided the question of Russian involvement and stressed that the incident would not change "our long-term relationship with Georgia."
Meanwhile, in Prague, the EU is set to launch its Eastern Partnership - a new neighbourhood policy towards Georgia, Ukraine, Armenia, Azerbaijan, Moldova and Belarus, where president Saakashvili is also due to attend.
The embattled Georgian president has been facing opposition street protests since 9 April calling for his resignation over the failed August war and lack of democratic reforms.
Georgia is of key importance to Europe, as it is a major transit route for oil and gas pipelines coming from the Caspian Sea and bypassing Russia.
An EU energy summit dedicated to this route dubbed the "Southern Corridor" is also due to take place in Prague on Friday.