An attack on a key hub and threats to tankers in the Strait of Hormuz are threatening supplies.

Footage circulating on social media shows thick, gray smoke billowing from the sprawling refinery complex along the Persian Gulf coast.

This comes after Saudi Arabia announced the temporary closure of one of its largest oil facilities following drone attacks.

Saudi Arabia warns of possible military action if Iran targets oil facilities after a drone strike on Ras Tanura, raising fears over Gulf energy security and global oil supply.

A concerted Iranian attack on Saudi oil facilities could trigger a military response from the kingdom, a source close to the Saudi government told AFP on Monday, after drones hit an oil refinery.

Saudi Arabia is increasing its oil production and exports as part of a contingency plan in case any U.S. strike on Iran disrupts supplies from the Middle East, two sources familiar with the plan said on Wednesday.