Russian President Dmitry Medvedev said Thursday after talks with US President Barack Obama that an ultimate solution to the long-running row over missile defence may not happen until after 2020.

Medvedev and Obama met on the sidelines of the G8 summit in Deauville, France, and also discussed the economy, counter-terrorism and Russia's pending entry into the World Trade Organization.

Before the summit, Medvedev had warned of the chances of a new Cold War in Europe should Washington build its missile system without the Kremlin's agreement, though other Russian officials played down the row.

Obama and Medvedev both looked stern-faced as they spoke to reporters after the talks, but both insisted that US-Russian ties, "reset" under the Obama administration, were in good shape.

Medvedev said the missile defence issue "will finally be solved in the future, like for example in the year 2020" by future politicians.

But he added that he and the US leader could "lay the foundation for other politicians," and called Obama his "colleague and political partner."

Obama said he and Medvedev were "committed to working together so we can find an approach and configuration that is consistent with the security needs of both countries... that maintains a strategic balance and deals with potential threats we both share."

Russia's recent tough talk and decision to test two nuclear-capable heavy missiles in the past month underscore a fear in Moscow that the Obama administration is paying lip service to the "reset" in relations announced by Washington in 2009.

Moscow has in recent months complained that it is being sidelined in talks over the joint missile defence for Europe and Medvedev's remarks may underscore the Kremlin's disappointment over the current negotiations.

The United States argues that the shield is meant only to protect Europe from nations such as Iran but has said nothing about Russian security safeguards.

Analysts note that Moscow is primarily worried the system will leave a permanent stamp on the security map of Europe and formalise the reduced role Russia plays in the post-Cold War world.