The US-Russia nuclear arms treaty to be signed this week enhances trust between the Cold War foes but Moscow may quit the pact if US missile defence plans go too far, a top Russian official said Tuesday.

The nuclear arms treaty to be signed by US President Barack Obama and his Russian counterpart Dmitry Medvedev on Thursday "reflects a new level of trust between Moscow and Washington," Foreign Minister Sergei Lavrov said.

Speaking to journalists in Moscow, Lavrov said the new disarmament treaty, which succeeds the 1991 US-Soviet START agreement, corresponds perfectly to the national interests of both the United States and Russia.

The previous pact was "born from the Cold War", he said. It contained much that was to the United States' advantage and "discriminatory" toward Russia -- an imbalance which will be wholly corrected in the new treaty, Lavrov said.

Lavrov stressed that the agreement to be signed this week in Prague explicitly acknowledges a direct link between offensive nuclear weapons and missile defence systems.

But he also admitted that the pact placed no restrictions on either side developing and deploying new missile defences, warning that US moves to do so could provide grounds for Russia to quit the treaty unilaterally.

"Russia will have the right to abandon the START treaty if a quantitative and qualitative buildup of the US strategic anti-missile potential begins to significantly affect the efficiency of Russia's strategic forces," Lavrov said.

He spoke to reporters amid US media reports that Obama plans on Tuesday to unveil a radical overhaul of the US nuclear arms strategy, placing explicit new limits on the use of such weapons.

In an interview with The New York Times, a senior US administration official said the new strategy would stress non-nuclear deterrence but would also make exceptions for "outliers like Iran and North Korea."

US commentators have described the new US-Russia START pact as a key step toward an eventual total elimination of nuclear arms, a generations-old disarmament goal that has been revived by the Obama administration.

Asked to comment on how Russia felt about a nuclear-free world, Lavrov was circumspect.

"To talk seriously about practical steps towards a world without nuclear weapons, attention should be drawn to a whole range of factors that could potentially upset global strategic stability," he said.

Chief among those, according to Lavrov, is the deployment of weapons in space, an area that previous US administrations have acknowledged work in and that Lavrov said Russia and China wanted to make off-limits.

Regulation of conventional weapons deployed by air, land and sea with huge destructive power, should also come under greater scrutiny, he said.

Lavrov added that US missile defence systems at their current stage of development do not threaten Russia.

"The first phase has to do with a regional system, which does not harm strategic stability and does not pose a risk to Russia's strategic nuclear forces," Lavrov said.

Plans under the previous US administration of George W. Bush to site US anti-missile batteries in Poland and a radar in the Czech republic were strongly opposed by Moscow.

The new US-Russia treaty limits each side to a ceiling of 1,550 deployed nuclear warheads, a reduction of around 30 percent by comparison with the 1991 START treaty.

Critics however say counting gimmicks and the current state of the US and Russian nuclear stockpiles make the new pact more a symbolic document than a real nuclear weapons-reduction tool.

earlier related report
Nuclear treaty boosts Russia bid to regain stature: analysts
Moscow (AFP) April 6, 2010 - The signing of a new US-Russian nuclear arms treaty Thursday will advance Moscow's cherished goals of restoring its lost influence in the world and regaining "parity" with Washington, analysts say.

When Russian President Dmitry Medvedev meets his US counterpart Barack Obama for the signing in Prague, it will hark back to Cold War days when Soviet and US leaders held the world in suspense as they debated nuclear arms cuts.

Analysts say Russia's leaders long for those days. For since Moscow lost its Communist empire, it has had to struggle with domestic problems such as a declining population and the North Caucasus insurgency.

During the lengthy talks, Russian negotiators pushed hard for every line in the treaty to reflect the principle of Russia-US parity, said Yevgeny Volk, head of the Moscow office of the Washington-based Heritage Foundation.

"This was one of the Kremlin's main goals in the talks on this treaty. It succeeded in getting US recognition of Russia's status as an equal partner in nuclear disarmament negotiations," Volk told AFP.

Moscow's political establishment sees many of the US-Russian treaties of the 1990s as unfavourable to Russia, Volk said. And that includes the 1991 Strategic Arms Reduction Treaty (START), which the new treaty will replace.

START called for US inspectors to be based round the clock at Russia's main missile plant in Votkinsk, around 580 kilometres (360 miles) northeast of Moscow. Yet Russia recalled its inspectors from similar US sites in 2001.

From that point on, the presence of the US inspectors had irritated Moscow, until they finally left Votkinsk just hours before START expired last December.

Medvedev's top foreign policy advisor, Sergei Prikhodko, said Friday that US inspections at Votkinsk would not continue under the new treaty.

Russian officials have also said the new treaty will address some of their concerns about US missile defence, a major source of friction between Moscow and Washington.

Moscow argues that Washington's missile defence plans could eventually lead to an impenetrable US shield that would allow the United States to carry out a first strike on Russia without fear of retaliation.

Missile defences were long banned by the 1972 Anti-Ballistic Missile (ABM) Treaty, but former US president George W. Bush unilaterally quit the ABM treaty in 2001 and pursued plans to build missile defences in eastern Europe.

Moscow had hoped to impose limits on missile defence in the new treaty, but settled for a compromise in which Washington acknowledged there was a linkage between strategic offensive and strategic defensive systems.

Though the Kremlin has touted the "linkage," both Russian and US officials say the new treaty would not stop the United States from building new missile defences.

"This is a big propaganda defeat for Russia since it had made missile defence such an important issue during negotiations," defence analyst Alexander Golts wrote in The Moscow Times newspaper last week.

Russia had also failed to get US negotiators to agree to other demands, such as deeper cuts in the number of vehicles capable of delivering nuclear warheads, he said.

"Moscow gave in to practically all US demands," Golts wrote.

But the more important thing may be that Russia has established itself as the United States' equal partner, as Obama pursues ambitious goals in disarmament and nonproliferation.

"There is no other country in the world with which the United States would sign a treaty on a basis of full, equal parity of interests," said Fyodor Lukyanov, editor of the journal Russia in Global Affairs.

"From this viewpoint, the new treaty is undoubtedly very important to Russia," Lukyanov told AFP.