Israel must ‘immediately and unconditionally’ release Saif Abu Keshek and Thiago de Avila, UN rights office spokesperson says.

The United Nations has called for the immediate release of two Gaza-bound humanitarian aid flotilla activists abducted by Israeli authorities last week, calling for an investigation into the “disturbing accounts of severe mistreatment”.

Israel must “immediately and unconditionally” release activists Saif Abu Keshek and Thiago de Avila, where they continue to be held without charge, UN rights office spokesperson Thameen al-Kheetan said in a statement on Wednesday.

The Spanish and Brazilian nationals were among dozens of activists who had set sail for Gaza as part of the Global Sumud Flotilla, which was intercepted by Israeli forces in international waters off Greece on April 30.

Flotilla organisers say that among about 180 activists, just these two were taken to Israel, where they remain in jail.

“It is not a crime to show solidarity and attempt to bring humanitarian aid to the Palestinian population in Gaza, who are in dire need of it,” said al-Kheetan. “Disturbing accounts of severe mistreatment of Abu Keshek and Avila must be investigated, and those responsible must be brought to justice.”

An Israeli court on Tuesday extended the activists’ imprisonment until May 10. They are on a hunger strike, drinking only water, since they were abducted last Thursday, organisers said.

No charges have been filed against the two men but they face several accusations, including affiliation with a “terrorist organisation and contact with foreign agents,” Adalah, the Israeli rights group representing them, previously told Al Jazeera.

Adalah said Abu Keshek and Avila have faced severe physical abuse while in Israel’s custody that amounts to “torture”.

On Wednesday, Teresa Regina de Avila e Silva,  Avila’s mother, died in Brasilia at the age of 63, the flotilla announced in a post on X. “She was a woman of remarkable joy and great strength,” the flotilla said.

“She faced years of serious illness with courage, serenity, and dignity, driven by an unwavering will to live and surrounded by the unconditional dedication of her family.”

The Global Sumud Flotilla’s first voyage to Gaza in August and September drew worldwide attention before Israeli forces intercepted those boats off the coasts of Egypt and Gaza in early October.

Crew members, including Swedish activist Greta Thunberg, were arrested and expelled by Israeli forces.

The UN spokesman al-Kheetan also called for an end to Israel’s use of arbitrary detention and of “broadly and vaguely defined terrorism legislation, inconsistent with international human rights law”.

He said the blockade on Gaza must end and humanitarian assistance in sufficient amounts must be allowed into the enclave.