An Israeli court on Wednesday rejected an appeal contesting the detention of two foreign activists seized by Israeli forces from a Gaza-bound flotilla, with rights groups representing them denouncing the ruling as unlawful. Saif Abu Keshek, a Spanish national of Palestinian origin, and Thiago Avila of Brazil were taken into custody after Israeli forces intercepted the flotilla in international waters off Greece on Thursday and transported them to Israel for questioning.

A Beersheva district court extended their detention until Sunday on Tuesday to allow police additional interrogation time, with the appeal filed by their lawyers later rejected the same day. The activists, who appeared in court with their feet shackled, have been on a hunger strike and have not been charged with any offense, according to their legal representatives.

Lawyers and rights groups accused Israeli forces of illegally arresting the activists on an Italian-flagged vessel in international waters and subjecting them to abuse in detention, including prolonged interrogations and confinement in cold cells. Israeli authorities denied the abuse allegations and stated both men were affiliated with the Popular Conference for Palestinians Abroad, a group Washington accuses of clandestinely acting on behalf of Hamas.

Spain, Brazil and the United Nations have called for the immediate release of the activists, with the UN rights office stating that solidarity efforts to deliver humanitarian aid to Gaza are not criminal acts. The flotilla had departed from European ports aiming to break Israel’s longstanding blockade of Gaza and deliver humanitarian assistance to the territory.

The court will resume hearing on the detention on Sunday, with the activists’ lawyers indicating they will pursue further legal avenues to secure their release while Israeli authorities maintain that security considerations justify the continued hold.