A top Russian diplomat suggested Thursday that the U.S. should not talk with non-NATO nations about a prospective missile shield, Russian news agencies reported.

Deputy Foreign Minister Sergei Ryabkov's remarks appeared to reflect alarm over the idea that Western-leaning neighbors such as Ukraine or Georgia, Russia's foe in a war last year, could potentially host U.S. missile defense facilities.

Ryabkov said Russia is concerned about what he said were contacts between the U.S. and nations outside NATO on missile defense, state-run ITAR-Tass and RIA Novosti reported.

President Barack Obama removed a major irritant in relations with Russia last month by scrapping U.S. plans to place interceptor missiles in Poland and a radar in the Czech Republic — deployments Russia treated as a threat.

The Kremlin has praised Obama for the decision, but Russian officials have also said they want to know details about what system the U.S. will put in place instead.

Ryabkov's comments served as a warning that the United States should avoid taking steps that would threaten Russia or turning to its neighbors as potential partners in missile defense without consulting with Moscow.

"We are experiencing the concerns that emerge when major questions of strategic stability should be considered in a partner-like manner," he was quoted as saying.

Russia and the U.S. have discussed cooperating on missile defense, and Ryabkov represented Russia in talks on the issue in Moscow on Monday ahead of Secretary of State Hillary Rodham Clinton's visit.

Ryabkov did not name any specific nations as being in contact with the U.S. about missile defense, but he spoke in response to a question about Russian media reports suggesting the U.S. was in talks with Ukraine on the possibility of using its radar stations as part of a missile shield.

The U.S. has not held negotiations with Ukraine regarding the use of Ukrainian radar stations, a U.S. Defense Department spokesman, Maj. Shawn Turner, said Thursday.

Tensions over Georgia and uncertainty over the future of Ukraine, whose pro-Western president wants the country to join NATO, are hurdles in efforts by Russia and the U.S. to mend strained ties.