Spanish authorities have arrested the leader of the banned Basque separatist party Batasuna, after the supreme court upheld his prison sentence on charges of praising terrorism.

Party officials say police arrested Arnaldo Otegi Friday in the northern Spanish city of San Sebastian as he was preparing for a news conference.

A lower court convicted Otegi in 2006 of glorifying terrorism during a Basque separatist rally three years earlier. It sentenced him to 15 months in prison. Otegi, whose party is the political wing of the ETA terrorist group, was free pending the Supreme Court decision.

ETA had declared a ceasefire last year. But the group formally ended the 15-month truce Wednesday and said it was resuming its fight for creation of an independent Basque state in northern Spain and southwestern France.

Spain suspended peace talks with ETA after ETA took responsibility for a bomb blast at the Madrid airport in December that killed two people.

More than 800 people have been killed since 1968, when ETA launched its terrorist campaign.

Spain's high court banned the Batasuna Party in 2002 under laws authorizing such action against political parties found to support terrorism.

Some information for this report was provided by AFP and Reuters.