By Steve Gutterman

MOSCOW (Reuters) - Russia signaled on Thursday that a change in U.S. plans for a European anti-missile shield could help the two sides make progress towards resolving a dispute that has frayed their relations.

On Friday, the United States announced it would station 14 new anti-missile interceptors in Alaska after North Korea threatened a pre-emptive nuclear strike, and forgo a new interceptor that would have been deployed in central Europe.

Cold War-era foes Moscow and Washington have long been at loggerheads over the shield in Europe. President Barack Obama's move in 2009 to scale down earlier, Bush-administration plans only offered a short-lived respite. Russia's main concern is that the European shield would weaken its nuclear deterrent.

Russia's point man for U.S. relations, Deputy Foreign Minister Sergei Ryabkov, said on Thursday the planned changes brought a new element to the issue. He called for further dialogue, noting Moscow still had concern that U.S. missile defenses could threaten its security.

Ryabkov's remarks were more upbeat than Russia's initial, critical reaction to U.S. Defense Secretary Chuck Hagel's announcement of changes in U.S. global missile defense plans on Friday.

"There is no unequivocal answer yet to the question of what consequences all this can have for our security," Ryabkov said.

"The causes for concern have not been removed, but dialogue is needed - it is in our interest and we welcome the fact that the American side also, it appears, wants to continue this dialogue," he told reporters.

In Brussels, a senior U.S. defense official said Russia was "not a factor" in the U.S. decision to change missile defense plans but there was hope it would allay Russian misgivings.

"Does this change their perception of U.S. intent ... with the missile defense program? We would certainly hope so and would welcome such a change, but only they, in the end, can decide," said the official, briefing journalists on the condition that he was not further identified.

"We hope they will give it serious consideration and then come, we hope, to the correct conclusion that this is further evidence that NATO's missile defense plans ... do not threaten Russia."

U.S. plans for anti-missile defenses have ruffled relations with Russia since Ronald Reagan's 1980s presidency and caused more tension since U.S. President George W. Bush pulled out in 2002 from a Soviet-era treaty limiting their development.

Obama helped usher in a period of warmer relations with a 2009 decision to scale down the Bush blueprint for a European anti-missile shield. But Moscow soon began warning that the revised U.S. plans also presented a threat.

Ties between Moscow and Washington, both veto-wielding members of the U.N. Security Council, have soured since the return of Vladimir Putin, a former KGB spy, to the Kremlin last May. There have been disputes over human rights and security issues, including the war in Syria.

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Washington says the anti-missile shield it has begun to deploy in Europe in cooperation with NATO nations is meant to counter a possible threat from Iran and poses no risk to Russia.

But Russia has said the shield would eventually enable the West to shoot down some Russian intercontinental ballistic missiles, tipping the post-Cold War balance of power, and has aired suspicions that this is the underlying aim of the system.

In its first official reaction, the Foreign Ministry said on Monday that Moscow would stick to its demand for binding guarantees that the system would not threaten Russia's security.

Washington is highly unlikely to satisfy that demand because of concerns about circumscribing any American missile defense development or giving the Kremlin a say in U.S. defense policy.

Ryabkov said the United States had given Russia more information about its plans during his talks in Geneva this week with Rose Gottemoeller, the U.S. acting under-secretary of state for arms control and international security.

"The material is interesting - it brings something new into this situation," Ryabkov said. "(But) I would not venture to say now whether the decisions made by the (U.S.) administration are a plus or more of a minus."

(Additional reporting by Adrian Croft; Editing by Mark Heinrich)