HELSINKI (Reuters) - Russian proposals for a new security pact in Europe are redundant and an attempt to weaken NATO, a senior U.S. diplomat said on Thursday

Russian President Dmitry Medvedev says the NATO military alliance is a Cold War relic, and his foreign minister used a meeting of the Organisation for Security and Cooperation in Europe (OSCE) to outline Moscow's ideas for an alternative.

But the meeting in the Finnish capital of the 56-nation security and human rights organisation highlighted the deep divisions between Moscow and Washington.

The fallout from Russia's war with Georgia in August, condemned by many Western states as disproportionate but blamed by Moscow on Georgia and its allies in the West, has also caused friction at the two-day conference.

U.S. Deputy Assistant Secretary of State Matthew Bryza told Reuters in an interview that Russia's proposal for a new collective security pact was directed at NATO, which Russia says is encroaching on its sphere of influence.

"There is no need for some new architecture and it is pretty transparent, I think, what that's all about," Bryza said on the sidelines of the OSCE summit in Helsinki.

"I think it's about looking for an alternative to NATO which has worked so well. NATO makes Russia uncomfortable."

France, holder of the European Union presidency, has said it is willing to discuss the Russian proposal. But most states in Europe, while saying they will listen to Russia's ideas, have shown little enthusiasm.

"We don't need new international institutions to get things done," Dutch Foreign Minister Maxime Verhagen said. "We only need the common political will to make present institutions work as they were intended to do."

FIRST STAB

The OSCE is unique because it is the only major security body that includes Russia, Europe and the United States. Critics say that makes it an unwieldy talking shop but some diplomats say it could provide a framework for a new security structure.

Finnish Foreign Minister Alexander Stubb, whose country hold's the rotating OSCE chairmanship, said no firm decision had been taken on how to proceed with the Russian proposal.

"This is very early stages, we don't have anything concrete, as such, on the table as a proposal," Stubb told a news conference after a private lunch where Russian Foreign Minister Sergei Lavrov took part in discussions on the plan.

"I would imagine that if -- and I say this as a big if -- we start changing the basic structures of the OSCE, we're in for, I think, the long term. This was just the first stab at the discussion," he said.

The Kremlin accuses the United States of using NATO expansion -- in particular long-term plans to bring former Soviet Georgia and Ukraine into the alliance -- to encircle Russia with weapons and draw new dividing lines in Europe.

Moscow has suspended its compliance with a major arms control pact, the Conventional Forces in Europe (CFE) treaty, saying it gives NATO free rein to ramp up its forces on Russia's borders while preventing it from responding.

Some Western diplomats say their governments want Russia to pledge its commitment to the arms treaty before they will consider its new security proposals.

German Foreign Minister Frank-Walter Steinmeier offered to host talks on revamping the treaty. "We cannot allow the crisis in the CFE regime to lead to the loss of this pillar of European security," he said.