Spanish police overnight detained 36 suspected supporters of the militant Basque separatist group ETA, police sources said Tuesday. The suspected members of the illegal youth organization Segi were held in the northern Basque region and neighbouring Navarre.

The detainees included several suspected leaders of Segi. Police searched 34 addresses, and were looking for three more suspects.

The Spanish judiciary has increased pressure on organizations linked to ETA, which has killed more than 820 people since 1968.

Segi was outlawed in 2007, following a 2003 ban on the radical separatist party Batasuna, which was confirmed recently by the European Court of Human Rights in Strasbourg.