Yemen's Houthis said on Tuesday they had hit Saudi Arabia's Ras Tanura ‌oil refinery, the biggest in the kingdom, with a ballistic missile.

Yahya Saree, the Houthis' military spokesperson, said the strike on the refinery had caused a fire at the complex, ⁠which also includes a shipping terminal and is located on the Gulf, west of the Strait of Hormuz.

The Houthis also said they had attacked two military transport jets at Najran Airport and an airbase in Khamis Mushait, as well as the Saudi Defense Ministry building in Riyadh and Abha airport.

Saudi Arabia had carried out 81 airstrikes and missile attacks over the past 24 hours against Yemen, Yemen Press Agency cited the Houthis as saying.

There was ‌no ⁠immediate Saudi confirmation of the attacks.

On Tuesday afternoon, the Saudi Civil Defense briefly issued an air raid alert in the Saudi capital Riyadh.

Falling debris from the interception of two ballistic missiles over Riyadh caused material damage to a building, a construction site and a vehicle, the Saudi Civil Defense said later on Tuesday.

The Saudi-led coalition said it had intercepted and destroyed two ballistic missiles launched by ⁠the Houthis towards Riyadh.

(With input from Reuters)