The chairman of the U.S. Senate Armed Services Committee has said the country must seek close missile defense cooperation with Russia as the best means of protection against Iran.

Missile defense has so far been a major obstacle in Russia-U.S. relations, due to U.S. plans to deploy a missile shield in Central Europe, purportedly to defend against Iranian long-range missiles.

Sen. Carl Levin told a missile defense conference on Monday that the United States and Russia should work jointly to weaken the Iranian missile threat.

"U.S.-Russian cooperation on missile defense against Iranian missiles - even if we were simply to begin serious discussions on the subject - would send a powerful signal to Iran," he said. "Iran would face in a dramatic way a growing unity against her pursuit of dangerous nuclear technology."

Russia has consistently rejected the U.S. justification for the anti-missile radar and interceptors planned for the Czech Republic and Poland, and views them as a major national security threat.

However, Levin said that with cooperation the divisive issue could actually improve the atmosphere between Washington and Moscow.

"Missile defense could become a tool for positive change, rather than an impediment to better relations," he said.

At the same conference, Democratic Rep. Ellen Tauscher, a likely candidate for a top nonproliferation post in the administration of President Barack Obama, questioned the need for the missile shield.

"The argument that the U.S. would be naked against an Iranian threat unless we deploy the GMD [Ground-Based Midcourse Defense] system in Europe is simply not right," she said.

Last week Russia welcomed the Czech Republic''s decision to put off a parliamentary vote on the ratification of a deal to host a U.S. anti-missile radar.