The United States has put a Basque military leader and explosive expert, Aitzol Iriondo Yarza, on its list of terrorists.

The State Department issued a statement Thursday saying that Iriondo, a leader of the terrorist group ETA, is detained in France and awaiting extradition to Spain to face terrorism and murder charges.

The designation blocks any U.S. property in which Iriondo has an interest, and any assets he may have under U.S. jurisdiction are frozen. The statement says that the designation will help stem the flow of financial and other assistance to this ETA leader.

The State Department designated ETA as a foreign terrorist organization in 1997. The European Union also regards ETA as a terrorist group.

The armed group has killed more than 820 people in its four-decade-long campaign for Basque independence in northern Spain and southern France.

Combined efforts by Spanish and French authorities have led to arrests of hundreds of ETA members in recent years and reduced the organization's activities.

The State Department says that Spanish and French prisons together hold more than 750 ETA members and that about 100 still remain at large.