MOSCOW. Sept 11 (Interfax) - The head of a Russian foreign policy think tank has argued that a new Cold War involving "an unrestricted nuclear and conventional arms race" may break out between Russia and the United States in several years.

Russian-U.S. relations may sink into a serious crisis in a few years, and "domestic and political factors will aggravate the situation rather than help overcome the differences," a Russian Academy of Sciences report that was released on Tuesday quoted Sergei Rogov, director of the academy's U.S. and Canada Institute, as telling a meeting of the academy presidium.

Serious political, economic and military frictions exist between Moscow and Washington, Rogov said.

"If the present-day trends are sustained, an unrestricted nuclear and conventional arms race may be unleashed again in several years' time," he said.

At the same time, there are good reasons to expect Russian-American relations to seriously improve, he argued.

"There are quite large areas where Russia and the United States have shared or parallel interests. If there are breakthroughs there - for example, agreements on cooperation on missile defenses, armaments control, nuclear power, and the settlement of the Iran problem (Iranian nuclear program issue) - it will be possible not only to stabilize Russian-American relations but to also create effective mechanisms of partnership," he said.