A large plume of smoke and fire was seen near an Aramco facility in Riyadh on Saturday, according to a witness who spoke to Reuters, as attacks linked to Yemen’s Iran-aligned Houthis intensify.

Saudi authorities had not immediately confirmed the fire, while Aramco had not responded to a request for comment. There was also no immediate claim of responsibility.

The incident comes amid rising hostilities between Saudi Arabia and the Houthis, who have increased attacks targeting Saudi cities and energy infrastructure.

The Houthis said last week that they had attacked Aramco facilities in Yanbu with missiles and drones. Saudi Arabia said it had intercepted six ballistic missiles fired toward Taif and the Yanbu area but did not report damage to Aramco facilities.

Earlier in August, Saudi Arabia faced growing risks to its Red Sea oil exports after the Houthis declared a maritime embargo against the kingdom and claimed attacks on Yanbu and the Jazan refinery.

The attacks also affected shipping visibility. Shipping analysts said recent Yanbu crude loadings were conducted without continuous vessel-tracking signals, while Saudi crude accounted for about 90% of the record 2.17 million barrels per day loaded at Egypt’s Sidi Kerir terminal during the period.