Two of Spain's most wanted alleged terrorists and at least 16 other suspected members of the armed Basque separatist group ETA (search) were captured Sunday in a vast French-Spanish police operation, authorities said.

Mikel Albizu Iriarte (search) and Soledad Iparraguirre (search), a couple who had been on the run since 1993, were arrested near Pau in southwestern France, French investigators and Spanish authorities said. The pair, both aged 43, were with their son.

They had false papers and refused to answer questions but were identified by police agents, investigators said.

"The operation is very important," said Spanish Interior Minister Jose Antonio Alonso. He said at least seven homes were searched and police seized documents, weapons and explosives.

Spain's Interior Ministry put the number of suspects in custody at 21. The discrepancy with the French figure could not immediately be explained.

Some 140 French and Spanish police agents took part in the latest raids on both sides of the border. Seven weapons caches uncovered contained rocket launchers, assault rifles, munitions and explosives. Police also seized cash and documents, the French interior ministry said

Mikel Albizu, who uses the alias Mikel Antza, is thought to have become a top ETA leader 12 years ago after police devastated the separatist organization by arresting most of its senior members.

Albizu managed to escape another police raid last April that netted an ETA logistics chief, Feliz Ignacio Esparza (search).

Iparraguirre, who uses the alias "Amboto," is considered one of ETA's leading female members.

She comes from a family of ETA militants and became very active after her boyfriend was killed in a police raid when she was aged 20. She allegedly participated in dozens of attacks from 1984 through 1992 that killed a total of 15 people and injured more than 20 injured.

French authorities said all but one of the 16 other suspected ETA members were arrested in towns between Pau and Bayonne in southwest France.

The other suspect was arrested in the northern Spanish city of Burgos. He was identified as Pedro Maria Alacantaria-Mozota, a Spanish truck driver. He is thought to have planted bombs for ETA at power installations in September, and his wife was among those picked up in France.

ETA has carried out bombings and assassinations in Spain since the 1960s in a campaign for an independent Basque state. The armed group is classified as a terrorist organization by the European Union and the United States. It has claimed or been blamed for more than 800 deaths.

ETA militants have long crossed into peaceful Basque provinces of southwest France to take refuge or make plans. French and Spanish authorities closely cooperate to hunt them down.