MOSCOW/WASHINGTON (Reuters) - The United States signaled a willingness on Friday to slow plans for a missile defense shield in eastern Europe if Russia agreed to help stop Iran from developing nuclear weapons.

A ground-based Interceptor missile breaks cloud cover, shortly after launch from Vandenberg Air Force Base, California, September 1, 2006. REUTERS/Defense Department/Handout

Plans for the shield have contributed to a deterioration in U.S.-Russian ties over the past few years, but the new administration of President Barack Obama has said it wants to press the “reset button” and build good relations with Moscow.

“If we are able to work together to dissuade Iran from pursuing a nuclear weapons capability, we would be able to moderate the pace of development of missile defenses in Europe,” a senior U.S. administration official told Reuters.

It was the most explicit statement yet by an administration official linking the missile shield to Russia’s willingness to help resolve the international stand-off over Iran’s nuclear program.

He spoke as Undersecretary of State William Burns held talks in Moscow, the most senior U.S. official to do so since U.S. President Barack Obama took office last month.

Burns signaled the United States was ready to look at remodeling its missile defense plans to include Moscow.

“(Washington is) open to the possibility of cooperation, both with Russia and NATO partners, in relation to a new configuration for missile defense which would use the resources that each of us have,” Interfax news agency quoted him as saying. Burns gave no details.

In another sign that strained relations may be thawing, European Union foreign policy chief Javier Solana said U.S. Secretary of State Hillary Clinton would meet Russia’s foreign minister in Geneva next month.

The more flexible U.S. position on its missile shield addressed one of Russia’s chief complaints against Washington. Moscow viewed the plan to site missiles in Poland and a radar tracking station in the Czech Republic as a threat to its security in its traditional backyard.

U.S. Vice President Joe Biden told a security conference in Munich, Germany, last week that the United States would press ahead with the missile defense shield, but only if it was proven to work and was cost-effective.

TACKLING IRAN

The Kremlin has been pressing Washington to give ground on the missile shield in exchange for Russia helping supply the U.S.-led military campaign in Afghanistan.

But the U.S. official in Washington focused on Iran.

“The impetus for the deployment of the missile defense systems is the threat from Iran. If it is possible to address that, then that needs to be taken into consideration as you look at the deployment of the system,” the U.S. official said on condition of anonymity.

The United States has led a drive to isolate Iran over its nuclear program, which the West fears is a cover to develop atomic weapons and Tehran insists is for the peaceful generation of electricity.

Russia and the United States agree that world security would be threatened if Iran acquired nuclear weapons but they disagree over whether Tehran is actively pursuing a weapons program.

Moscow, which plans to start up a nuclear reactor at Iran’s Bushehr plant by the end of the year, has used its veto in the United Nations Security Council on a number of occasions to water down or defeat U.S.-led efforts to impose tougher sanctions on Iran.

Obama has said he is prepared to talk to Iran’s leaders and offered economic incentives if Tehran “unclenches its fist.” But he has also warned of tougher economic sanctions if Tehran does not halt its nuclear program.