UN Secretary-General Antonio Guterres has called for the “immediate and unconditional” release of all aid staff held by the Houthis in Yemen, Al Jazeera reports.

“Their continued arbitrary detention is unacceptable,” Guterres said in a statement, adding that the UN is working to secure their release.

The Houthis — which have been carrying out a military campaign against Israeli targets and vessels in the Red Sea and Gulf of Aden to protest Israel’s war on Gaza — have not commented on the latest detentions, Al Jazeera noted.

The detentions come after US President Donald Trump placed the group back on the US list of “foreign terrorist organisations”, the report further said.