The UN has suspended all staff movement in Houthi-held areas of Yemen after the Iran-backed rebels detained another seven UN employees. The UN secretary general, António Guterres, called for the “immediate and unconditional” release of all aid staff held in Yemen, which is suffering one of the world’s worst humanitarian crises. “Their continued arbitrary detention is unacceptable,” Guterres said in a statement on Friday, adding that the UN was working to secure the release of those being held. The Houthis have detained dozens of staff from the UN and other humanitarian organisations, most since the middle of last year. Following