Iran-backed Houthi rebels stormed the offices of two United Nations agencies in the Yemeni capital Sanaa on Sunday, a day after Israel said it killed the prime minister of the rebel-controlled government.

The offices the World Food Programme (WFP) and the United Nations children’s agency (UNICEF) were “entered by local security forces” on Sunday morning, spokespersons for the agencies told CNN in separate statements.

A WFP staff member was detained, as were a number of UNICEF staff members, according to the statements.

Hans Grundberg, the United Nations special envoy for Yemen, later confirmed that at least 11 UN personnel were detained, adding that he “strongly” condemns the detentions, as well as the forced entry into UN premises.

António Guterres, the UN’s secretary-general, also strongly condemned the Houthis’ actions, calling for “the immediate and unconditional release” of those detained by the rebel group.

Guterres noted that others working for the UN, as well as people working with NGOs, civil society and diplomatic missions, have been arbitrarily detained in Yemen since 2021.

“The personnel of the UN and its partners must never be targeted, arrested or detained while carrying out their duties for the UN,” he said. “The United Nations will continue to work tirelessly to secure the safe and immediate release of all arbitrarily detained individuals.”

The WFP and UNICEF are “urgently seeking additional information” from local authorities, their spokespersons told CNN, adding: “Our immediate priority is the safety and well-being of our staff.”

It is unclear whether the raids were related to Israel’s attacks. The Houthis have previously targeted the UN and other international organizations.

The information minister with the UN-backed government, Moammar al-Eryani, strongly condemned the Houthis’ actions, Yemeni state news agency SABA NEWS reported.

Meanwhile, Israeli Prime Minister Benjamin Netanyahu vowed that the strikes that killed Ahmed al-Rahawi, the prime minister of Yemen’s Houthi rebels, are “only the beginning” of his country’s campaign against the group.

Al-Rahawi was killed alongside other Houthi officials in a strike on Sanaa on Thursday, the head of the Houthis’ Supreme Political Council confirmed, vowing revenge for the attack.

The rebel group regularly launches missiles at Israel, as well as attacks on vessels in the Red Sea, in what it says is revenge for Israel’s offensive in Gaza.

Netanyahu has pledged that the Houthis will “pay a very heavy price for their aggression against the State of Israel.”

“We are doing what no one has done before us, and this is only the beginning of the strikes on senior officials in Sanaa - we will get to all of them,” the Israeli leader told a government meeting on Sunday.

Since 2014, Yemen has been split between a Houthi government which controls Sanaa and much of the north, and a rival but more widely recognized administration in the south.(CNN)

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