Russian Foreign Minister Sergey Lavrov said that Russia maintains its right to withdraw from a new arms proliferation treaty with the United States if it feels threatened by US missile defense plans. But he told reporters that the nuclear disarmament agreement represented a "new level of trust" between the two countries.

"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 nuclear forces," Lavrov said during a press conference held on Tuesday morning.

The new Strategic Arms Reductions Treaty (START), which supercedes the original 1991 agreement between the US and the Soviet Union, would reduce the number of deployed warheads by 30 percent to approximately 1,500.

Lavrov said the treaty addresses the link between offensive nuclear weapons and missile defenses, but it does not restrict development or deployment of missiles for either country. But he asked the US to forego plans to install such defenses in eastern Europe.

Missile shield still contentious

The administration of former US President George W. Bush had planned to build a missile shield in Poland and the Czech Republic, irritating Russia, which regarded the missiles as a threat. Bush's successor, Barack Obama, briefly scrapped the plans before announcing that a revised version would be built in Romania and Bulgaria. The US said the intent is to neutralize attacks from Iran.

Lavrov told reporters that steps toward a nuclear-free world required looking at other types of weapons control: the deployment of weapons in space, and greater regulation of non-nuclear but massively destructive traditional weapons.

"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," Lavrov said.

Russian President Dmitry Medvedev and US President Barack Obama are to sign the treaty in Prague on Thursday. Lavrov said he expects the Russian parliament and American Congress to ratify the treaty by the end of April.

svs/AFP/AP/dpa
Editor: Chuck Penfold