A human rights group has asked a Spanish court to indict four alleged former Nazi concentration camp guards and seek their extradition from the United States over the deaths of Spanish citizens, a lawyer said Tuesday.

The Brussels-based rights organization, Equipo Nizkor, names the suspects as John Demjanjuk, a retired, 88-year-old auto worker in Ohio who is also being sought by Germany; Anton Tittjung; Josias Kumpf; and Johann Leprich.

All four face deportation from the United States but no country is willing to take them in, the group said.

The group said it is acting under Spain's principle of universal jurisdiction. This states that war crimes, crimes against humanity, terrorism, torture and other heinous offenses can be prosecuted in Spain even if they are alleged to have been committed abroad.

Spanish judges have used the principle to go after the late Chilean dictator Augusto Pinochet, Al Qaeda leader Usama bin Laden and figures from Argentina's so-called "dirty war" of the 1970s and 80s, among other people.

In this case, Equipo Nizkor lawyer Gloria Trinidad said, the fact that thousands of Spanish citizens died in Nazi camps where the four suspects allegedly worked is another reason — although not a necessary one — for Spain's National Court to charge them.

The group's complaint says the suspects served as guards in the concentration camps at Flossenberg and Sachsenhausen, in Germany, and Mauthausen, in Nazi-occupied Austria.

Spaniards who ended up at these and other Nazi camps were mainly people from the leftist Republican side in the Spanish Civil War who fled to France and were captured while fighting German troops.

At Mauthausen alone, for instance, more than 7,000 Spaniards were incarcerated and at least 4,300 of them were killed, Equipo Nizkor said. It said this figure came from documents submitted to several courts, mainly the one that oversaw the Nuremberg trials that followed World War II.

The new lawsuit was filed at Spain's National Court on June 19.

The next step is for a prosecutor to issue a nonbinding recommendation on whether the court should agree to study the case. Then the court itself has to decide whether to accept the case and consider filing charges, Trinidad said. She said the process could take months.