Yemen's Houthis, also known as Ansar Allah, have released 290 hostages on Monday, the International Committee of the Red Cross said in a statement on Monday.
The IRCR said that the freed captives included 42 survivors of an attack on a detention centre in Dhamar earlier this month.
Earlier, Al Masirah TV reported that the movement was offering to release 350 hostages, including three Saudi Arabia nationals.
According to the head of the Houthis' prisoner affairs committee, the captives were in the lists included in the prisoner swap deal that had been agreed upon in Stockholm in December.
Reacting to the development, the United Nations Special Envoy for Yemen Martin Griffiths welcomed the move, saying it would hopefully lead to further progress on the prisoner swap deal.
The abovementioned deal makes part of UN Security Council resolution calling for a 30-day deployment of a United Nations team to Yemen to help monitor the ceasefire in Al Hudaydah during the UN-led consultations in Sweden.
According to the resolution, the troops of both sides of the conflict were supposed to withdraw from the area, exchange war prisoners and establish humanitarian corridors in Al-Hudaydah.
On Friday, Houthis reported an operation near Saudi Arabia's border with Yemen in which they "encircled three military brigades that were completely defeated". According to Houthi forces spokesman Gen. Yahya Saria, there were Saudi soldiers and officers among the captured after the battle, as well as many commanders and military personnel of other nationalities.
The operation comes against the backdrop of the drone attacks on Saudi Arabia that were claimed by the Houthis.
For several years, Yemen has been engulfed in an armed conflict between government forces, led by President Abdrabuh Mansour Hadi, and the Houthi movement. The Saudi-led coalition has been carrying out airstrikes against the Houthis at Hadi's request since March 2015.