Drone strikes targeted two Saudi Aramco oil facilities in Abqaiq and Khurais over the weekend, disrupting about half of the kingdom’s oil capacity, or about 5.7 million barrels per day. Saudi Arabian Energy Minister Prince Abdulaziz bin Salman said that the attacks are not only aimed at the kingdom, but also impact the global oil supply and thus pose a threat to the entire global economy.

Although Yemen’s Houthi rebels took responsibility for the attacks, U.S. Secretary of State Mike Pompeo pinned the strike directly on Iran stating, “Iran has now launched an unprecedented attack on the world’s energy supply. There is no evidence the attacks came from Yemen.” The development comes as Saudi Aramco intends to go public in what could be the world’s largest initial public offering.

Read more: Drone strikes knock out half of Saudi oil capacity