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By Oleg Shchedrov

MOSCOW, Sept 1 (Reuters) - Russia's decision to send troops to Georgia has set a new standard for defending its national interests and the United States must learn to live with it, Foreign Minister Sergei Lavrov said on Monday.

Russia crushed its southern neighbour in a brief war last month after Georgia tried to recapture by force its pro-Moscow, separatist region of South Ossetia. It drew Western condemnation by pushing far beyond the disputed area, bombing and deploying troops deep inside Georgia proper.

"Through its response to the Georgian aggression, Russia has set a kind of standard for reaction, which fully complies with international law," Lavrov told students of Moscow's diplomatic college in a speech to mark the start of the new academic year.

"Russia has returned to the world stage as a responsible state which can defend its citizens."

Any doubts about this should have been dispelled by its action in Georgia and recognition of two pro-Russian provinces as independent states, said Lavrov, whose harshest words were addressed to Washington and NATO.

"America needs to acknowledge the reality of the post-American world and start adapting to it," Lavrov said. "An attempt to live in its own unipolar world has gone on too long, and this is dangerous in every respect."

He added: "There is a feeling that NATO again needs frontline states to justify its existence."

However, he reiterated Moscow's commitment to continue dialogue with the United States.

"We will deal with any America," Lavrov said, urging Washington to exercise "reciprocity and absolute honesty" in ties. "We will continue talking to Washington as long as there is a tiny hope of understanding each other and making a deal."

"MOMENT OF TRUTH"

The speech, focused on new relations between Russia and the West, was made hours before EU leaders were due to gather in Brussels to discuss a common stance in the Georgian crisis. Lavrov made clear Russia would not bow to any pressure.

He was expounding new foreign policy guidelines set by President Dmitry Medvedev, who despite Western expectations of a softer line has formalised the assertive stance of his predecessor Vladimir Putin.

Medvedev said in a television interview on Sunday that Russia would adhere to international law but not accept a U.S.-led "unipolar world", and laid claim to specific spheres of national interest that Russia would defend.

Over the past few years, the West has been watching with alarm the increasingly assertive policy of a resurgent Russia, fearing a revival of Soviet-era imperialism.

Russia, in turn, has accused the West of building new lines of division in the world by failing to treat it as an equal.

Lavrov said the conflict in Georgia had come as a "long-cherished moment of truth", adding that "today's clarity is better than any ambiguity."

Europe's inability to produce a new collective security system, "open for everyone and taking into account everyone's interests", was to blame for the Georgia crisis, he said.

"Something should be done because otherwise Euro-Atlantic affairs will keep returning to square one."

Russia has proposed calling a security conference in Europe, to create new arrangements for neutralising threats in the continent.

It views NATO's eastward expansion and the deployment of parts of a U.S. missile defence system in Eastern Europe as a direct threat to its security. Plans to grant NATO membership to ex-Soviet Georgia and Ukraine are anathema for Moscow.

"In the absence of a reasonable multilateral dialogue we will be forced to react unilaterally," Lavrov said. "But we would indeed prefer joint work on European security issues." (Editing by Jon Boyle and Mark Trevelyan)

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