The Guardian newspaper says Washington is concerned the affair is destabilising democracy in Chile.

US Secretary of State Madeleine Albright reportedly raised the issue with the British Foreign Secretary, Robin Cook, twice in the past two weeks.

But US Defence Secretary William Cohen said on Sunday that Washington would not be getting involved in the tug-of-war between Spain, Chile and the UK.

He said: "Essentially this really is a dispute between Chile, Great Britain and Spain and will have to be resolved between those three countries.

'We will keep out of it'

"It is not something the United States can get involved with."

The 83-year-old former dictator was arrested in London on 16 October by British police acting on an international warrant from Spain.

A Spanish judge wants General Pinochet extradited to stand trial on charges of murder and torture.

Last week the Law Lords - the highest court in the UK - ruled he was not immune from prosecution, paving the way for the extradition procedure.

Mr Straw now has until 11 December to rule on whether the extradition process can continue.

The UK and Chile denied on Sunday they had struck a deal in which the 83-year-old former dictator would return home and face trial in Santiago.

History of collusion

Chile is a sensitive subject for the US, which has a history of supporting General Pinochet.

The CIA is widely believed to have helped the military during the coup which toppled the democratically-elected President Salvador Allende in 1973.

Shortly after the coup an outspoken critic of the regime, Orlando Letelier, was assassinated by Chilean agents in Washington.

Despite the dictatorial nature of his regime and its record of human rights abuses General Pinochet was a close ally of US Presidents Ronald Reagan and George Bush, himself a former CIA chief.

The US media remains divided on the issue.

The New York Times said recently Britain must extradite General Pinochet to Spain and resist the "false argument" that trying him would imperil Chile's democracy.

But the Wall Street Journal argued that General Pinochet's only crime was having saved his country from a Communist take-over orchestrated by the Cuban leader, Fidel Castro.