A Spanish judge has indicted three alleged former Nazi death camp guards on charges of being accessories to genocide and crimes against humanity.

Judge Ismael Moreno issued international arrest warrants against the three: Johann Leprich, Anton Tittjung and Josias Kumpf. Moreno said in a ruling issued Thursday that Kumpf apparently lives in Austria and other two in the United States.

The judge acted under Spain's observance of the principle of universal jurisdiction. This allows particularly heinous crimes such as genocide, torture or terrorism to be prosecuted in Spain even if they are alleged to have been committed elsewhere.

Moreno has been investigating since July of last year at the request of two Spaniards who survived the Nazi death camps.