Friends and former colleagues of Shaif al-Hamdani were uncertain if they would ever see him again.

Mr. al-Hamdani, a Yemeni who previously worked for the U.S. Embassy in Yemen, was arrested in 2021 by Houthi militants who had taken control of the capital, Sana. Following his detention, there was little information available regarding his situation or that of ten other Yemeni embassy employees arrested alongside him, aside from the fact that they were held due to their connections with the United States.

In June, Mr. al-Hamdani emerged in a troubling manner: he appeared in a propaganda video released by the Houthis, where he confessed to being a spy for the United States and Israel.

“Seeing Shaif in that blue prison jumpsuit, forced to confess under pressure, broke my heart,” shared Adam Ereli, an American diplomat who worked with Mr. al-Hamdani over two decades ago at the embassy.

The video surfaced shortly after the Houthis, an Iran-backed militia now dominating northern Yemen, initiated a new wave of arrests, detaining at least 27 staff members from United Nations agencies and various humanitarian organizations. In the following weeks, many more Yemenis involved with similar organizations were arrested.

This surge in arrests raised concerns of a broader crackdown on individuals associated with international organizations and foreign missions in Yemen. Over the past year, tensions between the Houthis and Western nations have escalated, particularly as the Yemeni militants have targeted international shipping in the Red Sea and launched missiles at Israel in solidarity with Palestinians in Gaza.

Conflict analyst Nadwa al-Dawsari noted that Houthi repression of U.N. and international personnel has persisted for at least five years. However, she suggested the latest arrests are more targeted, aiming to undermine local support for Western powers and institutions.

“The Houthis are deliberately targeting U.N. staff as a tactic to extract concessions by using them as hostages,” Ms. al-Dawsari stated. “They intend to control who works for U.N. and international organizations, installing their own members to monopolize international aid.”

Yemen faces one of the world’s most severe humanitarian crises, with over half the population—approximately 18.2 million people—requiring some form of humanitarian assistance, according to the U.N. This reality underscores the vital work of local and international humanitarian organizations.

The U.S. State Department condemned the recent arrests, accusing the Houthis of disseminating disinformation through forced confessions regarding the roles of current and former Yemeni U.S. Embassy staff.

“We are deeply distressed to see our colleagues treated this way; they have all been loyal to Yemen,” remarked Tim Lenderking, the U.S. special envoy for Yemen, in an interview. “These coerced confessions are completely fabricated. It’s a staged performance.”

The U.S. closed its embassy in Sana in 2015 following the Houthis’ takeover of the capital, with the ambassador now operating from Riyadh, Saudi Arabia.

It remains unclear if any charges have been filed against the recently detained individuals. Nonetheless, the Houthis have accused Mr. al-Hamdani and others arrested in 2021 of conspiring against Yemen, alleging they were part of an “American-Israeli spy cell.”

At least one detainee from June, Mohammed Naj Khamash, 55, reportedly died in Houthi custody last week, according to family members.

After the release of the video confessions, Houthi leader Abdul-Malik al-Houthi claimed that those arrested in 2021 had “subversive” intentions behind their humanitarian efforts.

In the video, Mr. al-Hamdani asserts that he acted under the direction of Mr. Ereli, the American diplomat.

“This video is both false and horrifying,” Mr. Ereli stated on social media in June. “Yes, Shaif al-Hamdani worked for me at the U.S. Embassy in Sana. No, neither of us were spies. We organized educational and cultural programs, with the Yemeni government’s approval, to foster independent institutions.”

After the Houthis took control of Sana in 2014, the internationally recognized government fled to Aden. A Saudi-led coalition launched a prolonged military intervention to oust the Houthis, which ultimately failed, leaving them in power over most of northern Yemen and its population.

The Houthis govern a poverty-stricken proto-state in northern Yemen with an iron fist. Previous detentions have highlighted a pattern of arbitrary arrests, according to reports from organizations like Human Rights Watch.

The Houthis have released polished videos, complete with music and graphics, showcasing other individuals besides Mr. al-Hamdani confessing to espionage.

The New York Times attempted to reach several relatives of the accused men, but all declined to speak out of fear of Houthi retaliation.

One Yemeni aid worker still in the country, who spoke anonymously due to safety concerns, described the repression in Yemen as reaching “terrifying” levels. This atmosphere, coupled with minimal media coverage and global interest, has made the repercussions of opposing the Houthis increasingly severe, the activist noted.

At least six Yemenis who closely knew Mr. al-Hamdani characterized him as a devoted citizen who dedicated his career to helping his compatriots. This has made it even harder for them to witness him being depicted as a traitor.

Hisham al-Omeisy, a notable Yemeni commentator who experienced torture during his own five-month detention by the Houthis, is closely following Mr. al-Hamdani’s case.

“We understand that the message behind these arrests is not aimed at the outside world but is intended to intimidate the everyday Yemeni population, signaling that there will be repercussions for collaborating with anyone other than the Houthis,” he explained.

“The extreme actions the Houthis have taken against their fellow Yemenis are profoundly short-sighted, callous, and inhumane,” commented U.S. ambassador to Yemen, Steven Fagin, regarding the recent arrests.

Despite such criticisms, the Houthis have continued their crackdown.

In August, they stormed the U.N. Human Rights Office in Sana, seizing documents, furniture, and vehicles. Volker Türk, the U.N. High Commissioner for Human Rights, condemned this as “a serious attack on the U.N.’s ability to fulfill its mandate.”

The U.N. confirmed that several humanitarian workers detained in June are facing potential criminal prosecution initiated by the Houthi authorities.

“The possible imposition of ‘charges’ against our colleagues is unacceptable and further exacerbates the prolonged incommunicado detention they have already endured,” stated a letter dated October 12 from various U.N. agencies and international organizations.

A potentially significant outcome of this crackdown is that it has prompted U.N. agencies and Western governments to reassess their operations in Houthi-controlled territories.

“This raises serious questions for the U.N. and these NGOs about their ability to continue functioning in Yemen, and if so, under what conditions,” Mr. Lenderking remarked. “We aim to assist the Yemeni people, but the Houthis are making it increasingly challenging to do so safely.”