Russia nuclear deal: Spin or deep cuts?

US President Barack Obama and Kremlin chief Dmitry Medvedev agreed to cut vast Cold War arsenals of operationally deployed nuclear warheads to between 1,500 and 1,675.

The pledge by Mr Obama and Mr Medvedev puts the world's two biggest nuclear powers further along the path to finding a replacement for the landmark 1991 Strategic Arms Reduction Treaty which expires on December 5.

But the cuts announced on Monday only take the US and Russia 25 operationally deployed warheads below the 1,700-2,200 range which both sides agreed to reach by 2012 under the 2002 Moscow Treaty.

"Within seven years after this treaty comes into force, and in future, the limits for strategic delivery systems should be within the range of 500-1,100 units and for warheads linked to them within the range of 1,500-1,675 units," according to the framework agreement.

After the cuts, the US and Russia will still have enough firepower to destroy the world several times over. Many hurdles remain to finding a replacement to Start by December.

Russia and the US are still haggling over what exactly constitutes a nuclear weapon and the Kremlin is deeply opposed to US plans for a missile defence system in Europe.

Finding agreement on a replacement for Start-1, signed by George Bush and Mikhail Gorbachev just months before the close of the Cold War, is seen by both sides as a way to "reset" relations after the friction of recent years.

Mr Obama and Mr Medvedev agreed at their first meeting in London on April 1 to pursue new reductions to strategic nuclear weapons and instructed negotiators to begin talks on a replacement for Start-1.

This was already a step forward because Mr Obama's predecessor George W. Bush showed little interest in a successor treaty to Start-1, arguing that it was not necessary. Mr Obama, however, has made nuclear disarmament a priority.

The aim is to reduce the number of deployed warheads below the 1,700-2,200 range which both sides agreed to reach by 2012 under a successor pact - known as the Moscow Treaty or Strategic Offensive Reductions Treaty - signed in 2002.

Officials say an agreement on Start would help Washington and Moscow to set an example to other countries ahead of talks next year on revising the Non-Proliferation Treaty.

But Russia and the US still currently hold 95 per cent of the world's nuclear warheads.

Russia is deeply opposed to US plans to station anti-missile batteries and radar detection systems in the Czech Republic and Poland as part of a global system to spot and shoot down hostile enemy rockets before they reach the US.

Washington says the system is intended to protect the US and its allies against a possible Iranian missile attack but Russia argues that the system could be used against its nuclear arsenal as well.

The Kremlin says the US anti-missile system is closely linked to Start negotiations and Moscow wants a resolution on missile defence before agreeing to a concrete deal on a replacement for Start.

"The questions of missile defence and Start are completely interlinked to the very core. There cannot be a final agreement on Start without a resolution of the missile defence issue," a senior Russian official said on condition his name was not revealed. "Think of a man with a sword and a shield against a man with just a sword - what does the second do? Get a longer sword, which amounts to an arms race which Russia does not want."

Mr Obama has rejected a link between arms control and missile defence, saying that Washington's plans do not threaten Russia.