Regional security and cooperation in the war against terrorism topped the agenda at talks between U.S. Defense Secretary Donald Rumsfeld and his Russian counterpart, Sergei Ivanov in St. Petersburg. The U.S. and Russian officials also discussed U.S. plans to update an early-warning radar system in Greenland.

The defense secretary says the radar is part of President Bush's plan to defend the United States and its allies against attack by so-called rogue states, and poses no threat to Russia.

Mr. Ivanov said Russia has "never ruled out" the possibility that Washington and Moscow might cooperate in developing anti-missile and anti-aircraft defenses.

However, there were areas of disagreement. Mr. Ivanov expressed Russia's concerns about American aid to the former Soviet republic of Georgia, warning that the situation there is, as he put it, "a very dangerous scenario."

Escalating violence in the breakaway region of South Ossetia inside Georgia has severely strained relations with Russia, which blames the increase in tensions on Georgia's new, U.S.-backed leader, Mikhail Saakashvili, who wants to reassert control over the area.

"This situation is not logical," Mr. Ivanov said. "For 10 years, all was normal there, and now we hear that our peacekeepers support one side of the conflict, which is nonsense."

Russian peacekeeping troops have been in South Ossetia since a cease-fire agreement ended a bloody conflict there a decade ago, but Georgia is now calling for the troops to be withdrawn.

Mr. Ivanov also told Mr. Rumsfeld that Russia remains unhappy with the enlargement of the NATO military alliance into more of Eastern Europe earlier this year.

He also reiterated Russia's long-standing position that the crisis in Iraq can be resolved only under the auspices of the United Nations.