Iran-backed Houthis on Sunday raided offices of the United Nations’ food, health and children’s agencies in Yemen’s capital, detaining 11 UN employees, officials said.

The rebels tightened security across Sanaa following the Israeli killing of their prime minister and several Cabinet members.

Abeer Etefa, a spokeswoman for the World Food Programme, told Associated Press that security forces raided the agencies’ offices in the Houthi-controlled capital on Sunday morning.

The UN official said armed forces raided the offices and questioned employees in the car park.

Ammar Ammar, a spokesman for Unicef, said a number of the agency’s staff were detained, and Unicef was seeking additional information from the Houthis.