Oman facilitated the release of 14 foreigners, including a British national, who were held in Yemen and transferred them from the Houthi-controlled Yemeni capital Sanaa to Muscat on Sunday, Oman's foreign ministry said.

The people freed included a British man, his wife and child, seven Indian nationals, a Filipino, an Indonesian, an Ethiopian and a Myanmar national, the ministry added, without giving details of what had led to their detention.

The British government identified the Briton as Luke Symons, saying he had been held without charge or trial since 2017.

"Luke was 25 when he was unlawfully detained by the Houthis. His son was only a few months old at the time," Foreign Secretary Liz Truss said in a statement.

"He was allegedly mistreated, in solitary confinement, and refused visits by his family," Truss said.

Amnesty International said in February that Symons traveled to Yemen in 2012 where he met and married his Yemeni wife. It said he had been accused by the Houthis, de facto authorities in North Yemen, of spying for the British government though he was not formally charged with any crime.

The Omani ministry said that after communicating with Saudi Arabia to facilitate issuance of the necessary permits, all 14 were transferred on an Oman Royal Air Force plane to the Omani capital, in preparation for their return to their countries.

A Saudi-led coalition, which intervened in the Yemen war in March 2015 against the Iran-aligned Houthis, controls Yemen's sea and air space. Oman is not a member of the coalition.

Earlier this month, the warring sides in Yemen's seven-year conflict agreed to a nationwide truce for the first time in years, under a U.N.-brokered deal.