An American oil worker who was kidnapped by Houthi rebels in 2017 in Yemen has been released, US President Donald Trump has announced.

Danny Burch "has been recovered and reunited" with his family, Mr Trump said on Twitter, thanking the United Arab Emirates for its assistance.

Mr Burch works for the Yemeni Safer oil company. He was abducted after taking his children to school.

Since 2015, Yemen has been locked in a brutal civil war.

His Yemeni wife said he was seized in the Yemeni capital Sanaa in September 2017 after dropping his children off at an event.

"They did it in broad daylight in front of everyone," Nadia Forsa told the New York Times at the time.

His brother told KLTV-News shortly after the kidnapping that Mr Burch had moved to Yemen in 2003 to work in the oil industry.

"His wife's there, he's got three children there, and I think even if he gets released, he'll stay," said Ronald Burch, adding that he had not spoken to his brother in 15 years and that he knew about the danger of kidnapping in the region.

"He knows as well as we do that that's the price of where he's at," he told the east Texas news station.

Reuters news agency reported in late January that he was taken to Oman aboard a flight along with other senior members of the Houthi leadership.

The Iran-backed Houthis have been fighting the US-supported government in the south of the country since 2015.

The US government has warned against traveling to Yemen because of "the high security threat level posed by ongoing conflict and terrorist activities" as well as the threat of kidnappings.

In September 2018, Human Rights Watch reported that Houthi militants had seriously abused detainees, including allegedly beating them with iron rods, shackling them to walls, and caning their feet.