At least nine Yemeni employees of United Nations agencies have been detained by Yemen’s Houthi rebels under unclear circumstances, authorities said Friday. Those held include staff from the United Nations human rights agency, its development program, the World Food Program, and one working for the office of its special envoy, according to officials.

The wife of one of those detained is also being held.

The UN has not yet provided a comment on the situation.

The Mayyun Organization for Human Rights confirmed the identities of the detained UN staffers and named other aid groups whose employees were also detained by the Houthis across four provinces under Houthi control: Amran, Hodeida, Saada, and Sanaa. These groups have not yet acknowledged the detentions. Additionally, it is believed that others working for aid groups have also been taken.

These detentions occur as the Houthis, who seized Yemen’s capital nearly a decade ago and have been fighting a Saudi-led coalition since shortly after, continue to target shipping throughout the Red Sea corridor in response to the Israel-Hamas conflict in Gaza.