MOSCOW - Russia signalled on Thursday that a change in US 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 the Democratic People's Republic of 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 US 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 US missile defences could threaten its security.

Ryabkov's remarks were more upbeat than Russia's initial, critical reaction to US Defence Secretary Chuck Hagel's announcement of changes in US global missile defence 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 US defence official said Russia was "not a factor" in the US decision to change missile defence plans but there was hope it would allay Russian misgivings.

"Does this change their perception of US intent ... with the missile defence programme? 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 defence plans ... do not threaten Russia."

US plans for anti-missile defences have ruffled relations with Russia since Ronald Reagan's 1980s presidency and caused more tension since US 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 US plans also presented a threat.

Ties between Moscow and Washington, both veto-wielding members of the UN 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.