The United Nations said it had suspended all its movements in Houthi-controlled areas in Yemen after the armed group detained a number of UN employees in the capital, Sanaa.
The United Nations said it is actively working with senior Houthi officials to try to secure the release of all its detained staff. No official statement has been issued by the Houthis yet.
This is not the first time that the group has detained United Nations employees, as a number of employees were detained last year. The Houthis also detained about 20 Yemeni employees at the US embassy during the past three years.
Human rights groups also accuse the movement of kidnapping, torturing and arbitrarily detaining hundreds of civilians.
The Iran-backed Houthis have been fighting the Saudi-led coalition in Yemen for nearly a decade. The conflict, which erupted after the Houthis overthrew the then-Yemeni government, has been largely at a stalemate for the past two years.
But the Houthis have attracted renewed international attention by targeting ships in the Red Sea and launching missiles toward Israel in the past 15 months, which they say is support for Hamas and the Palestinians.
Their actions led to retaliatory strikes on Houthi positions in Yemen by the US, Israel and the UK.
Since the start of the Gaza ceasefire, the Houthis have said they will reduce their attacks on ships and cease fire on Israel if it continues the truce.
However, one of President Trump's first actions upon taking office was to order the Houthis to do so Return him to the US list of foreign terrorist organizations.
Despite all this, the organization still controls large areas in Yemen.
The country was the poorest in the Middle East before the war began in 2015. Hundreds of thousands of people have since died in fighting or from disease and hunger exacerbated by the conflict.
UN agencies provide a vital lifeline to millions of Yemenis through their food and medical assistance.
But they regularly faced problems reaching people in remote areas outside main towns and cities, with Houthi officials regularly reported to be obstructing the delivery of humanitarian aid in areas they control.
