Thousands of Basques, supported by local political parties and unions, staged a rally Saturday in San Sebastian to protest against the arrest of 10 members of the Basque separatist camp earlier in the week, according to dpa. The protesters demanded the release of separatist leader Arnaldo Otegi and several others still in custody after they were rounded up in police raids in San Sebastian and Pamplona four days earlier. The rally was called by leftist-nationalist parties and unions, with the Basque Nationalist Party PNV, which until last May had ruled the region for nearly 30 years, also participating in the demos. Otegi and the others were arrested on accusations of seeking to re-establish the Batasuna party, seen as the political arm of the underground separatist group ETA. The party was banned six years ago. Otegi and four others are now in pre-trial custody, while the remaining five persons have since been released. The 51-year-old Otegi had long headed the Batasuna party. Press reports said he was believed to have met several times with top ETA figures in southern France over the past few months, travelling under the code-name "Ronaldinho." ETA, fighting for a separate Basque state, is listed as a terrorist organization by the European Union and the United States and blamed for more than 820 deaths since 1968.