A US military MQ-9 drone has been shot down in Yemen, two U.S. officials told Reuters on Wednesday, the second such incident in recent months.

A Houthi military spokesman had earlier said that air defences had brought down a US drone.

The officials, speaking on the condition of anonymity, said the drone, which is purported to be worth over $15 million, was shot down late on Tuesday.

A Houthi spokesman said an MQ-9 drone was brought down by a missile near the city of Dhamar, southeast of the Houthi-controlled capital Sanaa.

US Central Command said it was aware of the reports but did not immediately confirm them.

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This is not the first time a US drone has been shot down over the war-ravaged country. Two months ago, the US military said that Iran-backed rebels had shot down a government-operated drone with assistance from Tehran.

US forces have been engaged in a sustained campaign against Yemen's al Qaeda branch, known as Al Qaeda in the Arabian Peninsula (AQAP), including launching sporadic drone and airstrikes against targets in the country.

The Houthis, meanwhile, have used increasingly sophisticated weaponry since sweeping control of the country in 2015. Their use of launch long-range missiles against neighbouring Saudi Arabia, and their attacks on drones, has prompted accusations that they are being armed by Iran.

In Tuesday night's attack officials told Reuters that the Houthis had likely used a surface-to-air missile to down the aircraft.

The same official admitted to Reuters that losing a drone was expensive but it was not unprecedented and was unlikely to be followed by a signifiant response from Washington.

The other official warned that it was too early to tell who was responsible for the incident.

A separate official told CNN that the missile involved was provided by Iran. The official added that the Trump administration will publicly criticise Iran for the incident.

The Houthis, however, claimed that the rocket was "developed locally".

"The rocket which hit it was developed locally and will be revealed soon at a press conference," Yahya Saria, a Houthi military spokesman, said on Twitter Tuesday night.

"Our skies are no longer open to violations as they once were and the coming days will see great surprises," he added.