(BSS/AFP) - UN Secretary-General Antonio Guterres on Sunday voiced anger over the detentions of UN workers in Yemen and called for their "immediate and unconditional release."

"I strongly condemn the arbitrary detentions on 31 August of at least 11 United Nations personnel by the Huthi de facto authorities in Yemen in areas under their control," he said in a statement.

"I further condemn the forced entry into the premises of the World Food Programme, the seizure of UN property, and attempts to enter other UN premises in Sanaa."