``International law now recognizes a category of international crimes,'' lawyer Alun Jones told Britain's highest court, Parliament's House of Lords.
His arguments came on the first day of an appeal of a High Court decision that British authorities acted illegally Oct. 16 in arresting Pinochet on a Spanish warrant.
The High Court held last week that, as a foreign former head of state, the 82-year-old general has immunity from prosecution.
The present Chilean government says some 3,000 political opponents were killed or disappeared during Pinochet's 17-year rule, which began with the violent overthrow of a leftist government in a 1973 military coup.
In a key development for prosecutors, the five judges -- sitting in a room packed with reporters and lawyers -- overruled objections from Pinochet's lawyers and said they would hear arguments on legal points not raised at the initial hearing.
The new arguments include whether Pinochet was legally head of state during the first violent hours after the coup and whether developments in international law mean that Britain has a duty to hand over a person accused of murder, kidnapping and torture.
``We invite your lordships' house decisively to reject the repugnant notion, offensive to all ideas of human rights ... that a person has immunity from such crimes,'' Jones told the court.
``We could try a Vietnamese for torturing a Cambodian 20 years ago, once he is here,'' said Jones, lead lawyer for the Spanish judge seeking Pinochet's extradition, the Spanish government and British prosecutors.
The senior judge, Lord Justice Gordon Slynn of Hadley, interjected that whether international law has evolved to make Pinochet's arrest lawful ``seems to me to be one of the principal questions we have to decide.''
In Spain, lawyers for a Miami-based group opposed to Fidel Castro said they would file papers Thursday to ask a court to investigate whether the Cuban leader can be charged in Spain with genocide and other crimes.
Representatives of the Foundation for Human Rights said the group was inspired by the recent actions against Pinochet.
``Our position is that if Pinochet committed crimes during 17 years of dictatorship, then Fidel Castro certainly deserves public scrutiny for his crimes during 40 years,'' Mariella Ferretti, a spokeswoman for the foundation, said in a telephone interview from Miami.
Outside Parliament in London on Wednesday, some 20 demonstrators stood throughout the day-long hearing in Pinochet's proceedings, clustered around a banner saying ``Wanted: Augusto Pinochet.''
Pinochet, who is recovering from Oct. 9 back surgery, remained hospitalized under police guard in London.
In addition to Spain, six other European countries have extradition proceedings under way, but those likely would become irrelevant if the Lords free Pinochet.
If they uphold his arrest after the hearing, which is expected to continue into next week, a legal battle looms in British courts over extradition.
Whatever happens, Pinochet's troubles in London appeared to have ended his political career in Chile.
The Chilean government said Wednesday that upon returning home, he should quit politics and ask for forgiveness.
``Gen. Pinochet would do a great favor to his country by leaving political activity and assuming responsibility and somehow asking for pardon for the abuses,'' Interior Minister Raul Troncoso said.
He also backed a proposal to set up a commission in Chile to determine what happened to some 1,000 people still unaccounted for since Pinochet's rule.
Some Chilean political parties also want a legal panel to examine the possibility of Pinochet standing trial in Chile.
As a senator-for-life and under laws he initiated, Pinochet has so far had immunity from prosecution in Chile.
© Copyright 1998 The Associated Press