Suspected ETA leader arrested in France

"Thierry," is "in all probability the one who has the most political and military weight in the ETA terrorist group," Interior Minister Alfredo Perez Rubalcaba said at a hastily arranged news conference in Dakar, Senegal.

"This is not just another operation," Rubalcaba added, as he cut short his official tour of several African nations to return to Madrid.

In a joint French-Spanish police operation, four Spanish suspects, including Lopez Penz, were arrested late Tuesday at an apartment in Bordeaux, Rubalcaba said.

On Wednesday, a fifth Spanish suspect was arrested in Spain, and later, a French suspect was detained in France, Rubalcaba said. The French suspect is believed to have rented the apartment to four of the others.

The others arrested at the apartment were identified as Ainhoa Ozaeta Mendiondo, Igor Suberbiola and Jon Salaberria, CNN partner station CNN Plus reported.

Analysts say police consider Lopez Pena to have been among ETA "hard-liners" who wanted to come out fighting from ETA's unilateral cease-fire declared in March 2006.

That cease-fire, declared at a time when ETA had been on the defensive after a string of arrests, raised hopes for an end to nearly 40 years of ETA violence blamed for more than 800 deaths and thousands of injuries.

An ETA bomb at Madrid's airport in December 2006 -- during the cease-fire -- killed two men and caused heavy damage. Police suspect that Lopez Pena, 49, had a hand in that attack.