A German man held in Yemen has been freed with the help of Oman and was flown to the sultanate on Tuesday, said the official ONA news agency.
Authorities in Germany had approached Oman to negotiate the release of the man from the rebel-held capital Sanaa "for humanitarian reasons," it said.
The identity of the man remains unclear, as do the circumstances of his detention, including who seized him and when.
He was airlifted from Sanaa to Muscat on an Omani air force plane pending his return home, said ONA.
Yemen has been at war since September 2014, when Iran-backed Huthi rebels and their allies drove the government out of Sanaa and much of the country's north.
Oman is the only Gulf Arab country that has good relations with Iran and the rebels -- under fire from a Saudi-led military coalition.
It has previously negotiated the release of foreigners held in Sanaa.
In April, Omani armed forces evacuated an American from the capital following a similar request for assistance from the United States.
And in September, Oman helped to negotiate the release of a Briton, two Americans and three Saudis held by the Huthis.