ZURICH (Reuters) - Switzerland has agreed to extradite to Spain a woman convicted there of supporting the Basque separatist group ETA, rejecting her claim that she was tortured into confessing while in Spanish custody, Swiss justice officials said on Thursday.

Swiss authorities arrested the woman, who was not identified, in Zurich last April. She had been living under an assumed name in Switzerland since 2009.

The woman had fled Spain that year after a court sentenced her to six years and nine months in jail for supporting ETA, a sentence that was reduced this year to 3-1/2 years, Switzerland’s Federal Office of Justice said in a statement.

“The ETA activist could not credibly show that she was actually tortured in Spain,” it said. The woman has 30 days to appeal against the decision, which also hinges on her pending request for asylum in Switzerland, the justice office said.

ETA, which has killed more than 800 people over several decades and declared a permanent ceasefire six years ago, has been severely weakened in recent years after hundreds of its members were arrested and police seized several weapons stashes.