RIYADH — The Arab coalition forces to Restore the Legitimate Government in Yemen said that 15 Saudi prisoners are to be released by Houthis on Sunday, adding that the prisoner swap is in line with the Stockholm agreement. The official spokesman of the Coalition to Restore Legitimacy in Yemen Col. Turki Al-Maliki said in a press conference here on Sunday that the Yemeni government will release 681 prisoners, and the Houthi militia will release 400. "Fifteen Saudi prisoner of war will be released by Houthi militia as part of the Yemen prisoner exchange agreement," Al-Maliki added. Al-Maliki said Yemeni prisoner exchange agreement also includes the release of four Sudanese. Al-Maliki described the prisoner swap as ‘purely humanitarian'. The Coalition called on the Houthi militia not to undermine the efforts of the United Nation special envoy to Yemen Martin Griffiths.