Two U.S. nationals released by Houthi rebels

Two U.S. nationals have been released from captivity by Houthi rebels in Yemen, in what may have been a prisoner swap for some 250 Yemenis.

That's according to state media in Oman, who reported its Sultan Haitham bin Tariq played a role in the release of the Americans.

The U.S. nationals are Sandra Loli and Mikael Gidada, according to the White House.

Loli is an aid worker who'd been held for three years. Gidada is a businessman. The remains of a third, Bilan Fateen, will also be repatriated.

The 250 Yemenis, meanwhile, had been receiving treatment in Oman, which flew groups of them back to Yemen's city of Sanaa, according to the Oman media report.

The White House is thanking both the sultan and also Saudi Arabia's King Salman for securing the U.S. nationals' release.

Yemen has been devastated by a war that has killed more than 100,000 people between the rebel Houthi movement and fighters loyal to the Saudi-backed government.