The United Nations on Friday suspended all travel into areas held by Yemen’s Houthi rebels after more of their staff were detained by the rebels

The United Nations has announced that the Houthis, controlling northern Yemen, have detained several UN personnel. In response, the UN has suspended staff movement in Houthi areas while demanding their release.

The UN said that the Houthis who control northern Yemen had detained an unspecified number of UN personnel, and it was suspending movement in Houthi-led areas.

All official movement of U.N. staff into or within Houth-held areas had been suspended to protect the safety of staff. The U.N. was actively engaging with senior Houthi representatives to demand the immediate and unconditional release of all its detained personnel and partners.