Saudi Arabia's state oil giant Aramco shut its Ras Tanura refinery after it was hit by a drone, an industry source said on Monday, an apparent escalation on the third day of strikes across the region launched by Tehran in response to the U.S.-Israeli attack on Iran.

The Ras Tanura complex, on the kingdom's Gulf coast, houses one of the Middle East's largest refineries with a capacity of 550,000 barrels per day (bpd) and serves as a critical export terminal for Saudi crude.

Ras Tanura was shut as a precautionary measure and the situation is under control, the source said. Two drones were intercepted at the facility, with debris causing a limited fire, the Saudi defence ministry's spokesperson said on Al Arabiya TV, adding there were no injuries.

Its shuttering will likely add to supply anxieties as shipping through the Strait of Hormuz, through which around a fifth of global oil consumption flows, grinds to a near-halt after vessels were attacked around it on Sunday. Brent crude futures surged roughly 10% on Monday.

"The attack on Saudi Arabia’s Ras Tanura refinery marks a significant escalation, with Gulf energy infrastructure now squarely in Iran’s sights," said Torbjorn Soltvedt, Principal Middle East Analyst at risk intelligence firm Verisk Maplecroft.

"The attack is also likely to move Saudi Arabia and neighbouring Gulf states closer to joining U.S. and Israeli military operations against Iran."

Aramco did not immediately respond to an emailed request for comment.

The drone strike added to a wave of attacks on the region, including on Abu Dhabi, Dubai, Doha, Manama and Oman's commercial port of Duqm. Most of oil production in the Kurdistan region of Iraq, which exported around 200,000 bpd in February to Turkey, was shut down over the weekend as a precaution, field operators said.

Saudi Arabia's heavily fortified energy facilities have been targeted previously, most notably in September 2019 when unprecedented drone and missile attacks on the Abqaiq and Khurais plants temporarily knocked out more than half of the kingdom's crude production and roiled global markets.

Ras Tanura was attacked by Yemen's Iran-aligned Houthis in 2021, in what Riyadh called a failed assault on global energy security.