A drone was spotted on March 4 over Ras Tanura, home to the largest oil refinery operated by Saudi Aramco, raising fresh concerns about the security of critical energy infrastructure in Saudi Arabia.

The Ras Tanura complex had already been shut down on March 2 following another drone attack, The Caspian Post reports via foreign media.

A spokesperson for the Saudi Ministry of Defense said preliminary information indicates that the recent incident also involved an unmanned aerial vehicle. However, officials stressed that no damage was reported as a result of the latest attempt.

Ras Tanura is a key hub in global oil supply chains.