Putin 'optimistic'
 
Relations between Washington and Moscow have long been tested by US plans to install bases in Poland and the Czech Republic, two countries close to Russia.

Russia is also opposed to the eastward expansion of Nato and the US' support for Kosovo’s independence from Serbia, a long-term ally of Moscow.

Putin said that he felt "cautious optimism" that Russia would eventually reach agreement with the US over the missile shield, which Washington insists is not aimed at Russia.

And he said that Medvedev, who is set to become Russia's president in May, would represent Moscow on foreign policy at international meetings.

Bush said that he wanted to "to work through common problems" with Medvedev once he takes power.

For his part, Medvedev told Bush that he hoped to further develop bilateral relations "without interruption", Russian news agencies reported.

"Russian-American relations are a key factor in world security," Medvedev told Bush during the meeting at Sochi, Interfax news agency quoted him as saying.

"I would like to act so that our relations develop further without interruption," Medvedev was quoted as saying.