The alleged political leader of the armed Basque separatist group ETA and his partner were arrested Sunday along with 19 other accused ETA members during a police sweep in southwestern France, Spanish authorities said.

Calling the raid "historic," Spain's interior minister, Jose Antonio Alonso, said it had netted Mikel Albizu Iriarte, 43, who he said has run ETA since 1993.

Albizu's partner, Soledad Iparraguirre, 43, is accused of involvement in at least 14 murders and is considered by authorities to be the highest-ranking woman in ETA. She is also suspected of collecting, managing and distributing money the group raises through kidnappings and extortion of businesses.

The couple, who appear on wanted posters in government buildings throughout Spain, were caught with their son in a house they used sporadically in the French town of Salies de Bearn, authorities said.

The 19 other people arrested were described by authorities as part of the logistical support network for the outlawed group.

"The blow struck against the terrorist organization today is an important step forward on the road to peace and shows that the end and the defeat of ETA is possible," Spain's ruling Socialist Party said in a statement.

The Interior Ministry said Albizu organized and carried out the jailbreak in the 1980s of two ETA members who had been sentenced to 26 years in prison. In 1985, he fled to Paris.

Albizu, also known as Mikel Antza, allegedly took control of the group after ETA's senior leadership was arrested in a 1992 police raid.

Sunday's operation, four years in the planning, was a joint effort between French anti-terrorist police and the Spanish Civil Guard and is still underway. Police have so far seized about 900 pounds of explosives, dozens of guns including 20 submachine guns, grenade launchers, munitions, detonators and computers.

ETA members have long used southwestern France as a haven. But that refuge has increasingly come under pressure because of closer cooperation between the French and Spanish anti-terrorism units.

The group, which seeks to create an independent homeland in the Basque region of Spain and France, has been relatively quiet in the last year, staging few attacks. The lull has led authorities to wonder if ETA might finally be nearing its end.

But last week ETA released a video vowing to press on with attacks until it had met its goal of an independent state. "The conflict will end when the rights of our people are recognized and respected," the group said in the video, which featured ETA members wearing black ski masks.

Alonso, the Spanish interior minister, said that although the operation was a success, it did not completely debilitate ETA, whose initials in Basque stand for Basque Homeland and Freedom. "Despite this grave blow, we continue on maximum alert and won't let our guard down one single minute," Alonso said at a news conference.

ETA is classified as a terrorist group by the Spanish government, the European Union and the U.S. State Department.

Mikel Albizu Iriarte was arrested with 20 other suspects.