Accused ETA leader Mikel Irastorza is arrested by French police on November 5, 2016 in the French town of Ascain, near the Spanish border.

Story highlights

Mikel Irastorza is detained in a joint French-Spanish operation in southwestern France

Spanish authorities allege he is the leader of Basque separatist group ETA

CNN  — 

Security forces have arrested the alleged leader of the Basque separatist group ETA, Spain’s interior ministry said, in what is described as a “hard blow” to the militant organization.

Mikel Irastorza, 41, was detained Saturday in the town of Ascain, near the border with Spain in southwestern France, in a joint French-Spanish operation, the interior ministry statement said.

Irastorza, who had been on the run since 2008, had been in charge of ETA activities for the past year and was the most senior ETA member still at large, the ministry said, following the arrest of the group’s previous leader.

His arrest represents a “hard blow” to ETA, it said, “because it involves a leadership loss within the organization and the elimination of its management structure, which was responsible for administering the weapons and the explosive arsenal.”

Two other people were arrested with Irastorza, the statement said. They’re accused of collaboration with ETA and giving shelter to Irastorza in their house, the statement added.

Listed as a terrorist organization by Spain, the United States and the European Union, ETA is blamed for more than 800 deaths in its decades-long fight for an independent Basque state that it wants carved out of sections of northern Spain and southwestern France.

In 2011, ETA announced “a definitive cessation of its armed activity,” raising hopes that decades of separatist violence might finally be over.

Authorities have continued their efforts since then to arrest the group’s members.

CNN’s Sofia Fernandes contributed to this report.