Yemen's Houthis have hit jet fuel tanks at Riyadh's main airport with drones, a bad sign for oil markets and for stability across the Middle East.

• The strike set the airport's main jet fuel tanks on fire, with a huge smoke plume visible for miles, according to Reuters.
• It is the first Houthi attack on the Saudi capital's airport in four years, marking a sharp escalation.
• Saudi Arabia also lost one of its most advanced fighter jets to the Houthis earlier this week.
• Oil prices were already rising, and more attacks on Saudi energy sites threaten supplies shipped around the world.

Outlook: Expect oil prices to climb further and the risk of a wider regional war to grow if strikes on Saudi infrastructure continue.