The Iran-backed group also detains people associated with the US embassy in Sanaa and aid groups.
The United Nations has suspended all travel into areas held by Yemen’s Houthis after more of its staff were detained by the Iran-backed fighters.
The statement on Friday came a day after the Houthis also detained individuals associated with the shuttered United States embassy in Sanaa, Yemen’s capital, and aid groups.
“Yesterday, the de facto authorities in Sanaa detained additional UN personnel working in areas under their control,” the UN statement read.
“To ensure the security and safety of all its staff, the United Nations has suspended all official movements into and within areas under the de facto authorities’ control.”
The UN did not say how many people were held in the latest swoop by the Houthis but added that it was “actively engaging with senior representatives” of the group, which has held Yemen’s capital since 2014.
The Houthis have been at war with a Saudi-led coalition battling on behalf of Yemen’s exiled government since 2015.
The Houthis did not immediately acknowledge the UN’s decision, which came as they have been de-escalating their attacks on shipping and Israel after a ceasefire was reached in the Israel-Hamas war in Gaza.
However, the Houthis have run a campaign targeting UN staff, aid workers and others for some time.
The group has also been airing repeated programmes on television channels they control, parading people they describe as working with Western intelligence agencies or the Israelis.
On Wednesday, US President Donald Trump reinstated a “terrorist” designation he had made on the group during his first term in office that was revoked by President Joe Biden, potentially setting the stage for new tensions with the rebels.
Yemen is experiencing one of the world’s worst humanitarian crises in which more than 18 million people need assistance and protection, according to the UN.
The war in the country has also killed more than 150,000 people, including fighters and civilians.
