Saudi oil giant Aramco has shut down operations at its Ras Tanura refinery following “a drone strike” amid Iran’s retaliatory strikes across Gulf countries.

Ras Tanura, one of Saudi Arabia’s refineries that processes about 550,000 barrels of crude per day, was shut down on Monday, after Tehran launched strikes across the region in response to the U.S.-Israeli attack on Iran, Reuters reported, citing an industry source familiar with the matter.

The report stated that Aramco is assessing the “damage” caused by the drone strike while the refinery is altering operations.

Iran has fired several missiles at U.S. bases in Gulf countries, including Saudi Arabia, after the U.S. and Israel launched deadly airstrikes on Iran, killing the country’s Supreme Leader Ayatollah Ali Khamenei and some of his regime officials.

At least 40 members of Mr Khamenei’s regime were killedin airstrikes over the weekend.

A report by Washington Post on Sunday alleged that Saudi’s crown prince, Mohammed bin Salman, secretly lobbied Mr Trump to attack Iran, while publicly calling for a diplomatic solution between the two countries.