A suspected leader of the Basque militant group ETA who was allegedly behind the shooting deaths of two Spanish guardsmen was arrested Monday by French police, officials said.

Counterterrorism agents carried out a pre-dawn raid to detain Mikel de Garikoitz Aspiazu Rubina in the town of Cauterets, near France’s border with Spain, police said.

The 35-year-old Spaniard known by the alias “Txeroki” is the reputed head of ETA’s commando units. He was arrested along with an unidentified Spanish woman, a police official said, speaking on condition of anonymity because he was not authorized to speak publicly.

Police seized a handgun, documents and a computer from the hideout, the official said.

President Nicolas Sarkozy hailed the arrest as a sign of cooperation between French and Spanish police.

The ETA leader is suspected of having a role in the shooting deaths of two Spanish civil guard officers in December while they were conducting an intelligence operation in the coastal French town of Capbreton.

He was described in Spanish media reports as one of the most wanted members of ETA, a violent hard-liner who opposed the cease-fire that ETA declared in March 2006 and the subsequent peace talks it held with the government of Spanish Prime Minister Jose Luis Rodriguez Zapatero.

ETA ended that truce in December 2006 after the negotiations failed, detonating a massive car bomb at Madrid’s Barajas airport and killing two people.

ETA has led a struggle to create an independent homeland straddling northern Spain and southwest France since the late 1960s. The group’s violence has claimed more than 800 lives.

After the arrest of two ETA militants announced last week, the French Interior Ministry said 31 suspected ETA members have been arrested in France this year.

(This version CORRECTS spelling of Aspiazu and full name of suspect.)