The United States does not expect any breakthrough on its missile defense talks with Russia this year, because 2012 is an electoral year for both countries, a senior U.S. official said here on Wednesday.

"It is clear that probably the sides won't achieve a breakthrough," the U.S. Special Envoy for Strategic Stability and Missile Defense Ellen Tauscher told a press conference ahead of an international conference on missile defense issues due on Thursday.

Washington expects to continue its talks with Russia on the U.S. -led NATO missile defense system in Europe after Vladimir Putin's inauguration as president on May 7, she said.

Meanwhile, Tauscher stressed that the U.S. would not agree to any restrictions on the missile defense system, but promised that Washington is willing to make a political statement that the system will not target Russia.

She added that the United States will also try to preserve strategic stability with Russia.

"It is very important to keep strategic stability between the U. S. and Russia," she said.

Moscow has long opposed the deployment of the U.S.-led NATO missile defense facilities near its borders and wanted legally binding guarantees from the U.S. and NATO that the missile defense shield is not targeting Russia.

President Dmitry Medvedev warned in last November that Russia might station missile defense systems, including the Iskander, in western and southern sections of the country if there were any additional U.S. missile deployments in Europe.