The U.S. Embassy in Riyadh was attacked with two drones, according to initial estimates, resulting in a limited fire and minor material damage to the building, a Saudi Defense Ministry spokesperson said on Monday. The big picture: In the latest incident to hit a U.S. ally since Tehran began a wave of counterattacks following weekend airstrikes by American and Israeli forces on Iran, the United States Mission to Saudi Arabia issued a "shelter in place" notification for Riyadh, Jeddah and Dhahran following the attack. Zoom in: The mission said it was limiting non-essential travel to any military installations in the region, adding: "We recommend American citizens in the Kingdom to shelter in place immediately." Hours earlier, Mora Namdar, the assistant secretary of state for consular affairs, issued a statement calling on Americans to " DEPART NOW " from Israel, Bahrain, Egypt, Iraq, UAE, Saudi Arabia, Kuwait, Lebanon, Qatar, Oman, Syria, Yemen, and Jordan "due to serious safety risks." Go deeper: Earthquake in the Gulf: Iran war expands to dozen countries in 72 hours Editor's note: This is a breaking news story. Please check back for updates.