Yemen's Houthis released 153 prisoners on Saturday with support from the International Committee of the Red Cross (ICRC), the ICRC said in a statement.
The identities of the prisoners were not disclosed, but the ICRC said they had received regular visits by the organization in Yemen's capital, Sana'a.
Who was released?
They included older people and the wounded and were released for humanitarian reasons, the Houthis' Committee for Prisoners' Affairs said in a press conference.
It marked the second such release after one last year.
There was no immediate indication that any UN personnel were freed after the global body said on Friday that seven of its personnel had been seized. Last year, 11 UN staff members were seized.
The Iranian-backed Houthis have controlled most of Yemen, including Sana'a, since seizing power in 2014 and early 2015.