Yemen’s Houthis have said they have arrested an “American-Israeli spy cell”, days after the Iran-backed group detained nearly a dozen UN personnel.

The alleged cell includes former employees of the US embassy in Yemen, according to a televised statement by Houthi intelligence chief Abdel Hakim al-Khaiwani.

“American-Israeli espionage cells carried out espionage and sabotage activities in official and unofficial institutions for decades in favor of the enemy,” he says.

“Members of the spy ring and US officials took advantage of their positions at the US Embassy to carry out acts of sabotage. Even after the US Embassy left Sana’a, members of the spy ring continued to implement their subversive agenda under the cover of international and UN organizations.”

Israeli government officials had no immediate comment, and the United Nations declined to comment on the allegations. The US State Department did not immediately respond to a request for comment.

UN spokesman Stephane Dujarric said the agency was working to secure the release of its 11 detained staff members, who work for five different UN agencies and the UN envoy for Yemen.

In a series of raids, armed Houthi intelligence officers also detained three staff members of the US-funded pro-democracy group the National Democratic Institute and three employees of a local human rights group, three officials from Yemen’s internationally recognised government told Reuters on Friday.

The Houthi Al Masirah TV has posted several videos on its Telegram channel purportedly showing statements from some of those arrested. Reuters could not independently verify these videos.

The Iran-allied Houthis have attacked ships in the Red Sea they say are showing solidarity with Palestinians during the Gaza war, prompting air strikes by the US and Britain.

For the past three years, they have been holding hostage about 20 Yemeni employees of the US Embassy in Sanaa. The embassy closed its operations in 2014.