A United Nations staff member who was recently detained by Yemen’s Houthi authorities has been released, UN spokesperson Stephane Dujarric said on Wednesday.

“We continue to urge the de facto authorities to immediately and unconditionally release all UN and humanitarian workers who are supporting the most vulnerable people in Yemen,” Dujarric said.

He did not provide information about the timing or circumstances of the detention, which comes after nine other UN personnel were detained by Houthis.

Dujarric said 53 UN staff remain detained by Houthis, adding that some have been held since 2021.

Yemen has been the focus of one of the world’s largest humanitarian operations during a decade of civil war that disrupted food supplies. WFP says it provided assistance to 15.3 million people, or 47 percent of the population, in 2023.

WFP was among the UN offices raided by Houthis in the Yemeni capital Sanaa in August. Eleven UN personnel were detained as a result of the raid.

The raid, which followed an Israeli strike on Sanaa that killed the prime minister of the Houthi-run government and several other ministers, was condemned by UN Secretary-General Antonio Guterres, who described the detentions as “intolerable.”

Houthi officials said last month that the UN personnel’s legal immunities should not shield espionage activities.

The Houthi-run foreign ministry also accused the UN of bias for condemning what they called “legal measures taken by the government against spy cells involved in crimes,” while failing to denounce the Israeli attack.