LONDON -- Lawyers argued in a British court Monday for the release of former Chilean dictator Augusto Pinochet, but he now faces moves for his extradition not only from Spain, but also from Switzerland and France.

Pinochet's lawyer, Clive Nicholls, told the High Court that as head of state at the time of the alleged murder and torture, Pinochet was immune from prosecution and had ``continuing immunity'' as a former head of state through international law and the Vienna Convention.

But Alun Jones for the Crown Prosecution Service argued that Pinochet could not claim diplomatic immunity.

``The functions of a president of Chile do not include the systematic torture and elimination of his political opponents,'' he told the panel of three senior judges.

The state prosecution lawyer said Pinochet was involved in the death of ``at least 4,000 people'' and sent agents to Spain to ``seek out and kill'' dissidents and political opponents.

Aircraft on standby

A Chilean military aircraft with medical facilities remained on standby at a Royal Air Force base at Brize Norton, 100 miles west of London, ready to transport him home.

Chile's ambassador to Britain told Santiago radio Monday that Pinochet was recovering normally from a back operation and is receiving the best of medical care.

Pinochet was arrested Oct. 16 in a London hospital at the request of two Spanish magistrates investigating the death and disappearance of Spaniards and others during his 1973-1990 military regime.

A Spanish court will decide Thursday whether Spain is competent to pursue Pinochet for the crimes he is accused of. But any decision to proceed has to be approved by the Spanish Cabinet.

The U.S. State Department said that over the past year it has been helping the Spanish judges investigating Pinochet.

Swiss, French join in

Adding to the moves for extradition from the Spanish judges were those from within Switzerland and France.

The Geneva public prosecutor, Bernard Bertossa, said an investigation had been opened into the disappearance in 1977 of a Swiss national, Alexei Jaccard, in Buenos Aires.

Interpol confirmed Monday evening it had received a request from Swiss federal police, acting on behalf of a Geneva judge, to keep Pinochet under arrest with a view to his extradition to Switzerland.

And William Bourdon, a lawyer for three French families, said Monday he would ask the French judicial authorities to start procedures for Pinochet's extradition ``right away.''

According to Bourdon, Pinochet's state police killed Enrique Andres Maria Ropert-Contreras, a French national and the son of the personal secretary to deposed President Salvador Allende, when he was 20.

French nationals Rene Chanfreau, 23, and Etienne Pesle, 49, both disappeared after being arrested by Chilean officials.