The UN's human rights chief Volker Türk demands that the Houthi movement "immediately and unconditionally" releases UN personnel and other aid workers being held captive.
On Monday, the Iran-backed movement claimed to have caught a "spy network", after aid workers, including eleven UN staff, were kidnapped last week.
"I categorically reject the scandalous accusations against our staff and am deeply concerned about the conditions in which they are being held", says Türk in a statement.
