Spain's National Court agreed Friday to review evidence in a lawsuit filed against four alleged former Nazi concentration camp guards.

A decision by the court to file charges in the case could lead to the four men's extradition from the United States to face trial over the deaths of Spanish citizens.

The lawsuit _ filed on behalf of victims' relatives by Brussels-based rights group Equipo Nizkor _ asks the court to charge the four with genocide and other crimes. It names John (Iwan) Demjanjuk, Anton Tittjung, Josias Kumpf and Johann Leprich as defendants.

Judge Ismael Moreno said Friday that his court would review the evidence in the suit, which claims the suspects served as guards in concentration camps at Flossenberg and Sachsenhausen, in Germany, and Mauthausen, in Nazi-occupied Austria.

The case states that more than 7,000 Spaniards were incarcerated at Mauthausen, and at least 4,300 of them killed, the judge said in a statement. Most Spaniards who ended up in Nazi camps were leftist Republicans who fled to France during the Spanish Civil War and were captured while fighting German troops.

The lawsuit was filed under Spain's principle of universal jurisdiction for cases dealing with charges of genocide, war crimes, terrorism, torture and other heinous offenses, regardless of where they were allegedly committed. There is no statute of limitations for a genocide charge.

The four suspects live in the United States. Equipo Nizkor said U.S. authorities have tried for years to deport them, after they lied on their immigration papers about their Nazi pasts.

Demjanjuk, who was born in Ukraine, is now an 88-year-old retired auto worker in Ohio and is also being sought by Germany.

Leprich, 82, was born in Romania and has lived in the Detroit area. Kumpf, 83, was born in what is now Serbia and lives in Racine, Wis., and 83-year-old Tittjung's listed address is in Kewaunee, Wis. He was born in what is now Croatia.

The Simon Wiesenthal Center in Jerusalem helped Equipo Nizkor to prepare the lawsuit.