HAMILTON, Canada 

The UN on Wednesday said 12 international staffers who were held in a UN compound in Yemen have departed the capital Sanaa on a UN Humanitarian Air Service flight.

"Earlier today, 12 UN international staff who were amongst those previously held in the UN compound in Yemen departed Sana'a on a UN Humanitarian Air Service flight. Three other staff who were detained in the compound are free to move or travel," said a statement by the UN spokesperson's office.

However, the UN said "53 UN colleagues remain arbitrarily detained by the de facto authorities, "besides personnel from non-governmental and civil society organizations and diplomatic missions.

"The UN, at all levels, continues to be seized with the matter and is in constant contact with the relevant authorities in Sana’a and with concerned Member States and partners to secure their release," it added.

The UN reiterated Secretary-General Antonio Guterres' call for the "immediate and unconditional release" of all aid personnel held by the Houthis.

The statement follows an incident last week in which Houthi forces stormed a UN residential compound in Sanaa and detained UN staff.

Yemen remains mired in one of the world’s worst humanitarian and economic crises, fueled by nearly a decade of war between government forces and the Houthis.