According to the Spanish Interior Ministry, Josu Ternera, head of the Basque guerilla group Euskadi Ta Askatasuna (Homeland and Liberty), commonly known as ETA, has been detained by Spanish and French authorities in the city of Sallanches in the French Alps.
READ MORE: Madrid Going to Continue Probe Into ETA Crimes Despite Group's Dissolution
Ternera, who is believed to be seriously ill, recorded a "final declaration" back in May 2018, announcing the complete dissolution of ETA.
Over 800 people have fallen victim to violent attacks carried out by ETA, which was established in 1959 in order to force the Spanish and French governments to recognise an independent Basque state.
Despite the group announcing a ceasefire in 2011, and then dissolving itself last year, Spain continues to investigate ETA's actions and prosecute some of its former members.