Yemen's Ansarullah fighters, also known as Houthis, have released Yemeni president's chief of staff, 10 days after his arrest, Press TV reported.
Yemen has been the scene of tensions since the Shia fighters arrested Ahmed Awad bin Mubarak on January 17.
The official was handed over to a committee of mediators on Tuesday. Ansarullah had accused Mubarak of being an agent for the United States.
His detention sparked clashes in the capital Sana'a, following which President Abd Rabbuh Mansur Hadi and his cabinet ministers resigned.
The president's resignation is yet to be finalized as a Sunday-scheduled parliament session to decide on the issue was not held.
The impoverished Arab country is currently grappling with a severe political crisis between the central government and Ansarullah fighters.
UN envoy Jamel Benomar voiced his happiness at Mubarak's release, urging the Houthis to "take all measures that could reassure other political groups and the Yemeni people."
Mubarak's release "will ease tensions and will push forward dialogue," he said.
The leader of Houthi Ansarullah movement has, meanwhile, accused some foreign powers of conspiring against Yemen and its nation amid the political tensions in the Arab country.
Addressing thousands of his supporters in the northern city of Sa'ada on Tuesday, Abdul-Malik al-Houthi censured political factions in cahoots with some regional states, noting that they want to ignite conflicts and create problems in Yemen.