Washington's new missile shield plans for Eastern Europe will not affect nuclear arms reduction talks with Russia, the U.S. ambassador to Moscow said on Thursday.

Bulgaria and Romania said they were in talks with the United States on hosting elements of its missile shield on their soil. The planned deployment of U.S. interceptor missiles into the Black Sea region triggered fierce criticism from Moscow, which is finishing up negotiations with Washington on a new nuclear arms cuts treaty.

"We have been holding extensive discussions on our plans to deploy interceptor missiles," U.S. Ambassador John Beyrle told reporters in St. Petersburg, reiterating they did not pose a threat to Russia.

Beyrle said the treaty to replace the Strategic Arms Reduction Treaty (START 1) - the cornerstone of post-Cold War arms control, which expired on December 5 last year - would be signed shortly. "We are working on final details," he said.

The planned deployments in Bulgaria and Romania come after President Barack Obama scrapped earlier plans for a radar and interceptor missiles in the Czech Republic and Poland, which Russia opposed as a national security threat and a blow to its nuclear deterrent.

Russia insists that there is a direct link between cutting the nuclear arsenals of the two countries and curbs on their ability to build missile defense systems.

Russian President Dmitry Medvedev pledged with Obama in April 2009 to sign a new deal as part of broader efforts to "reset" bilateral ties strained in previous years.

ST. PETERSBURG, February 18 (RIA Novosti)