Yemen's armed Houthi movement said on Wednesday it had launched a drone strike on a facility belonging to oil giant Saudi Aramco in southern Saudi Arabia - though the company said its plants there were operating "normally and safely".

The Houthis' Al-Masirah TV channel did not say when the attack took place or give details of any damage.

"The air force announced the execution of air strikes with the Qasef-1 aircraft on Aramco in Jizan (province)," the channel said on its Twitter account, referring to a drone the Houthis unveiled last year.

Saudi Aramco operates a 400,000-barrel-per-day refinery in Jizan, part of a new economic city on the Red Sea.

Al-Masirah said the Houthis had also launched an attack with the same model of drone on the airport of Abha in neighbouring Asir province.

Saudi Arabia and a coalition of mostly Gulf Arab states intervened in Yemen's civil war in 2015 to try and push back the Houthis after the movement drove the internationally recognized government into Saudi exile.

The Houthis have stepped up ballistic missile attacks on the kingdom in what it says is retaliation for the air raids.

The group unveiled what it said was a series of drones, including the Qasef-1, at a ceremony last year.

The arms monitor Conflict Armament Research (CAR) said it had evidence showing the Qasef-1 and other Houthi kit was made in Iran and was not of indigenous design and construction "in contrast to Houthi statements".

The coalition accuses the Houthis of being armed and supported by Iran - charges the group and Tehran deny.