UN chief warns 'Son of Star Wars' could start new nuclear arms race

America came under heavy pressure yesterday to reduce its arsenal of nuclear weapons and draw back from plans to shield itself from missile attack by rogue states.

Kofi Annan, the UN secretary general, warned that the US proposal to deploy a missile defence system could lead to a new arms race and set back moves toward nuclear disarmament. Speaking at the opening of a month-long review of the Nuclear Non-Proliferation Treaty, Mr Annan said: "It is my hope that all states will take great care to weigh these dangers and challenges before embarking on a process which may well reduce, rather than enhance, global security."

The 1970 treaty is widely seen as the best hope of achieving a measure of global nuclear disarmament and security, but the decision by India and Pakistan to test nuclear weapons in 1998 undermined the agreement. It also caused widespread pessimism about hopes for nuclear peace. Neither country is a signatory; nor is Israel, a state known to have a nuclear capacity. The treaty is a pact between nuclear and non-nuclear states, with the former committed to reduce their weaponry and the latter promising not to seek nuclear status.

But as the superpowers show diminishing concern about disarmament and developing nations push to nuclear status, the underlying political basis of the treaty is in doubt.

Only five countries - the United States, Russia, Britain, France and China - are allowed to have nuclear arms under the treaty, and the other 182 signatories are supposed to renounce them.

The Russian parliament's decision to ratify the Start II and Comprehensive Test Ban treaties gives Moscow some moral advantage as the session opens. It will also put pressure on the US to make some move to show that it is still committed to reducing the nuclear threat. But America is moving towards "Son of Star Wars", adefence scheme that would shield it from attack by a rogue state with nuclear missiles.

The rest of the world views this as an attempt to withdraw from the Anti-Ballistic Missile Treaty. The French President, Jacques Chirac, said last year: "If you look at history, since men began waging war, you will see that there's a permanent race between sword and shield. The sword always wins."

A group of neutral and developing states, known as the New Agenda Coalition, and led by South Africa, Ireland, Brazil, Mexico, Sweden, Egypt and New Zealand, will press the world's nuclear states for further action.

Madeleine Albright, the US Secretary of State, was to deliver a defence of American arms control strategy yesterday as the meeting opened. America has also been criticised for moves that its adversaries see as stalling the process of arms control.

But the US Congress has refused to ratify the test ban treaty, and is showing few signs of interest in arms control. It wants to push ahead with a tougher defence posture, and Republicans are keen to get a national missile defence in place as soon as possible.