Washington said on Wednesday that it denounced Houthi militant detentions of UN staff, as well as, American mission staff in Yemen.
"The United States strongly condemns the recent detentions by the Houthis of United Nations, diplomatic and non-governmental organisation staff," said Matthew Miller, spokesman for the State Department.
"We also strongly condemn the Houthis' efforts to spread disinformation regarding the role of detained current and former US mission local staff through televised forced and fake 'confessions'."
Abdel Hakim Al Khaiwani, the Houthis' intelligence chief, on Monday announced that the group had arrested what it called an "American-Israeli spy cell" in the capital.
They claimed that the cell operated out of the former US embassy and northern Yemen.
Houthis released alleged confession videos by at least 10 Yemenis, who said they were locals recruited to work for US operations in the country.
But the US suspended its embassy operations there in 2015.
"These Houthi actions reflect a blatant disregard for the dignity of the Yemeni people and individuals who, contrary to the Houthis' lies, have dedicated themselves to their country's betterment," Mr Miller said.
"Their detention, and that of the UN staff is an affront to diplomatic norms, and they should be released immediately. We will not rest until they are."
Houthis have detained UN and US staff in the past.
The UN this week confirmed that 11 staff members who worked for various UN agencies and the UN envoy for Yemen were detained, and that it was trying to co-ordinate their release.
“The Houthis should immediately release any UN employees and workers for other independent groups they have detained because of their human rights and humanitarian work and stop arbitrarily detaining and forcibly disappearing people," Niku Jafarnia, Human Rights Watch researcher for Yemen, said in a statement.
Iranian-backed Houthis have held some level of control over most of Yemen, which is also home to one of the world's worst humanitarian crises, since 2014.
The militants have fought off a Saudi-led coalition in recent years.
The group is also militarily attacking international maritime travel in the Red Sea and the Gulf of Aden over Israel's war against Hamas, which has renewed US and British attacks on their operations this spring.
Human Rights Watch has detailed how Houthi authorities have used taking hostages, arbitrary detention and enforced disappearances as an abusive tactic in enforcing their power in Yemen.
"Such detentions not only attack the rights of these individuals but also undermine essential humanitarian and human rights work in Yemen, at a time when the majority of Yemenis do not have adequate access to basic necessities like food and water," Ms Jafarnia said.
