US ambassador Richard Holbrooke said that members of the US Congress who oppose paying the funding arrears would also be doing "immeasurable damage" to the UN.

Holbrooke warned of a threat to national security

President Bill Clinton has vetoed a $39bn finance bill which did not provide funds to pay some of Washington's $1bn-plus debt.

And Mr Holbrooke said: "If we were to accept the bill in its present form we would certainly lose our vote in the General Assembly.

"The president stands for strong national security. This administration does and the overwhelming majority of the people of both parties in both houses of congress want a strong national security.

"We need to band together now to push back the forces of that small group of people who want to destroy US's national security interests and simultaneously do immeasurable damage to the UN."

BBC Washington correspondent Nick Bryants says some US politicians believe the UN is too bureaucratic and that some Republicans are ideologically opposed to funding through the UN, what they say are pro-abortion groups.

Vote at risk

Article 19 of the UN Charter says that a member state will lose its vote in the General Assembly if it is two or more years in arrears on its contributions.

A spokesman for Secretary General Kofi Annan said on Tuesday that the loss of voting rights was "automatic".

But the loss of its vote in the General Assembly would not affect the right of the United States to continue as one of the five permanent members of the Security Council.

The finance bill which President Clinton vetoed would have pushed "a key funding portion" of its UN arrears into a later year, Mr Holbrooke said.