Washington denounced the claim by Tehran today that it had test-fired a new surface-to-surface missile with a range of 2,000 kilometres (1,200 miles), capable of reaching Israel and US bases in the Gulf.

Mostafa Mohammad Najjar, Iran’s Defence Minister, said the new “Sejil missile” had “extremely high capabilities”. He was quoted as saying that “it will only land on the heads of those enemies who want to commit aggression and invade the Islamic Republic”.

Despite the claims of a new weapon system, Western experts said it was probably just another name given to the Shahab 3 missile which had been test-fired on previous occasions.

The timing of the latest launching was seen as a deliberate move by Tehran to try and deter either Israel or the US from taking military action against Iran over its suspected nuclear weapons programme before President Bush hands over to Barak Obama on January 20.

Gordon Johndroe, White House spokesman, said: “Iran’s development of ballistic missiles is contrary to United Nations Security Council resolutions and completely inconsistent with Iran’s obligations to the world.”

He said Iran should refrain from further missile tests “if they truly seek to gain the trust of the world”.

Andrew Brookes of the London-based International Institute for Strategic Studies said: "I think the Iranians just keeping on rejigging the same missile and putting a new logo on it. It's basically the Shahab 3 with a different name, and the purpose of the test firing is to tell the world, 'don't forget us', we have missiles that can reach 2,000 kilometres."

"However, the launching of these missiles is not that meaningful because the Iranians have not developed an advanced minituarised warhead to fit into the front end, unless they are getting help from North Korea or Russia, and Moscow says it is not supporting Iran's missile programme. So the missiles are rather like the Second World War V2 bombs which scared people but didn't cause mass casualties," he said.

Duncan Lennox, editor of Jane's Strategic Weapons, said: "You can never be sure with the Iranians. From the photographs they have released the missile looks like the Ashoura which they launched a year ago. It is a solid propellant missile with a triconic nose shape, like the teat on a baby's bottle. The Shahab 3A also has the same nose shape."

He added: "What is not clear is whether the test firing took place today or whether it's a photograph taken out of the archives but from the pictures it looks like a two-stage missile with a range of 1,900-2,000 kilometres."

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