RIYADH, (REUTERS) - Oman has helped locate a missing American and a Singaporean in Yemen and evacuated them to Muscat, its state news agency said on Monday, a day after unconfirmed reports in local media that United States citizens were being held by the Houthi militia group.

The pair travelled to the Omani capital after coordination with the "relevant authorities in Yemen", Oman News Agency reported, citing an official statement.

Oman is brokering talks between the Houthis and the United States to help find an end to Yemen's civil war.

Yemen's Houthi militia is still holding three US citizens, two of Yemeni and one of Somali origin, after the Singaporean and American who had been missing left Yemen for Oman, an official in Sanaa said.

The American of Somali origin had been detained by Yemen's government in Sanaa for several years on suspicion of links to Al-Qaeda before the Houthis seized the capital last year. It was not clear why the two others were being held by the Houthis.