The arrest of Mr Morales follows that of Rodolfo Almiron in Spain

Juan Ramon Morales is suspected of involvement in the Triple A, a right-wing paramilitary group which operated in the country.

Human rights campaigners say the death squads killed some 1,500 government opponents between 1973 and 1976.

Eighty-eight-year-old Mr Morales, who denies the crimes, was arrested in his home in the capital, Buenos Aires.

After refusing to testify before judges he was placed under house arrest at his home.

He is the second alleged member of the notorious death squad to be arrested in recent weeks.

In late December, Argentine Rodolfo Almiron was arrested in Spain.

Police superintendent Jose Ramon Morales was alleged to have been one of Mr Almiron's main collaborators.

The judge who issued the warrant said both Mr Morales and Mr Almiron are wanted in connection with "crimes against humanity" committed by the Argentine Anti-Communist Alliance, or Triple A.

The group was set up during Juan Domingo Peron's third and last presidency by Jose Lopez Rega, then minister for social welfare.

It continued to operate under the government of Peron's widow, Isabel, during which period most of the killings took place.