UN Secretary-General António Guterres on Tuesday condemned the death of a World Food Programme (WFP) staffer while in the custody of the Iran-backed Houthis.

In a statement, Guterres expressed his condolences to the family of the deceased staffer, who he said had been arbitrarily detained by Houthi authorities on January 23. He called for “an immediate, transparent, and thorough investigation, as well as accountability for those responsible,” emphasizing that the circumstances of the death “remain unclear.”

The UN is urgently seeking clarification from Houthi authorities. According to the organization, dozens of staff members from the UN, NGOs, civil society organizations, and diplomatic missions remain in Houthi detention—some for years.

Guterres described these arbitrary detentions as “unacceptable” and reiterated his call for the immediate and unconditional release of all detainees.

On Tuesday, the World Food Programme announced that Ahmed Baalawi, a staff member responsible for IT operations, had died in a Houthi prison in Saada, northern Yemen.