Tribal gunmen loyal to the Shiite-Houthi movement walk holding their weapons during a gathering against the Saudi-led intervention in the country in the Bani al-Harith area, north of the capital Sanaa, on August 6, 2015.
CNN  — 

Two Americans have been released from captivity in Yemen in exchange for the release and return of more than 200 Houthis who had been held in Oman, a top Trump administration official and another source said Wednesday.

US National Security Adviser Robert O’Brien said in a statement that Sandra Loli and Mikael Gidada were released from the custody of the Houthis – an Iranian-backed Shia political and military organization from the north of Yemen. According to the Wall Street Journal, who was first to report their release, Loli, a humanitarian worker, was held for three years and Gidada, a businessman, was held for one year.

In addition, O’Brien said that the remains of US citizen Bilal Fateen would also be repatriated.

In exchange, 271 Houthis being held in Muscat, Oman, were released and returned to Yemen’s capital Sanaa, a high-ranking source involved in the negotiations told CNN Wednesday.

A spokesman for the Houthi rebels – who control a large part of Yemen – said on Twitter that several hundred “wounded and stranded people from Yemen” had arrived in Sanaa on board planes from Oman.

“All the thanks and gratitude to the Sultanate of Oman for its humanitarian efforts with the Yemeni people,” the spokesman, Mohamed Abdel Salam, said.

An official with the Houthi rebels, Nasr El Din Amer, told CNN that he “does not confirm nor deny that Americans” were released as part of the deal.

In his statement, O’Brien offered “sincerest thanks to Sultan Haitham bin Tariq of Oman and King Salman of Saudi Arabia for their efforts to secure the release of our citizens.”

“President (Donald) Trump continues to prioritize securing the release and repatriation of Americans held hostage abroad. We will not rest until those held are home with their loved ones,” O’Brien said.

Yemen has been embroiled in a years-long civil war that has pitted a coalition backed by Saudi Arabia and the United Arab Emirates against the Iran-backed Houthi rebels. The conflict has cost thousands of lives and has plunged the country into a humanitarian crisis.

CNN’s Vivian Salama contributed to this report.