BAYONNE (AFP) -- French anti-terrorist police on Thursday arrested Mikel Karrera Sarobe, alleged to be the most senior commander of the armed Basque separatist group ETA still at large.

Officers stormed a residential block in the southwestern French city of Bayonne before dawn and arrested Mikel Karrera Sarobe along with two alleged accomplices -- his deputy and a female militant.
Spanish Interior Minister Alfredo Perez Rubalcaba said 37-year-old Sarobe was the new leader of the group's armed wing. This makes him the fifth ETA paramilitary chief to be arrested in just two years.
“He is currently the most senior leader of the terrorist group, the head of its military operations, the one who gives orders to ETA commandos,” he said.
The minister named the second male suspect as Arkaitz Aguirregabiria del Barrio and described him as the group's number two. Aguirregabiria is wanted in France for his alleged role in the March 16 shooting of a policeman.
The third suspect, also a Spanish national, is Maite Aranalde Ijurco. She is also a known ETA militant, the minister said. Two French citizens were arrested in a second raid as part of the same operation.
“We have two people, one the most wanted by Spanish police and the other the most wanted by French police. It is a great step forward,” said Rubalcaba.
Experts agreed that the arrests were a sign that ETA was finding it harder and harder to reorganize, with each new commander promoted to leadership quickly tracked down by French and Spanish cops.
“Nine months without an attack outside of a period of truce? I think that's a first since the return of democracy in 1975,” said Florencio Dominguez, head of the Basque news agency Vasco Press and author of several books on ETA.
Dominguez said that with five leaders falling in two years, the group could no longer elect a new chief quick enough for him to pass strategic decisions down to grassroots supporters, neutering its political influence.
For the past four decades ETA has been fighting a bloody campaign for an independent Basque homeland in the area populated by Basque speakers in a corner of northern Spain and southwest France.
It is listed as a banned terrorist group by the European Union and has been held responsible for the deaths of 829 people during its on-again off-again campaign of gun and bomb attacks on mainly Spanish targets.
Traditionally, ETA used France as a safe rear-base for attacks on Spain, but in recent years the two EU allies have strengthened cross-border police cooperation and cracked down hard on the group.
So, while ETA has not carried out any attacks on Spanish soil since August 2009, its cells are under increasing pressure in France.
In March, Basque gunmen killed a French policeman for the first time, gunning down 52-year-old Jean-Serge Nerin in a shoot-out that erupted during a routine identity check in the Paris suburbs.
French and Spanish official sources said that the alleged ETA number two, Aguirregabiria, was thought to have been involved in that shooting.
The officers who carried out Thursday's raid -- detectives from France's DNAT anti-terrorist squad and a special weapons team from the RAID police commando unit -- seized weapons, cash and computer equipment at the scene.
At the same time as the three Spanish suspects were being picked up in Bayonne, two French suspects were arrested in the nearby town of Urrugne as part of the same inquiry, French officials said.
The Spanish minister Rubalcaba identified this pair as Benoit Aramendi and Laetitia Chevalier and hailed the operation as “a magnificent example of police cooperation”.
Karrera Sarobe, alias Ata or “duck” in the Basque language, was identified as ETA's new military leader on a revised most-wanted list issued by Spanish police on March 16 in their pursuit of ETA militants.
More than 30 suspected ETA members have been arrested in 2010, including ETA's new leader Ibon Gogeascoechea Arronategui, who was captured in February in northwestern France.