"US citizens living and working near military bases and oil and gas facilities and other critical civilian infrastructure, particularly in the Eastern Province and areas near the border with Yemen, are at heightened risk of attack," said the US Embassy in Saudi Arabia.
The statement warned that there may be no advance warning of a missile or drone attack. The embassy urged American citizens to review precautions to take if an attack occurs.The Saudi Aramco oil processing facility was attacked by suicide drones and cruise missiles in September in an attack blamed on Iran.Tensions in the region have risen after IRGC Quds Force commander Qasem Soleimani was assassinated by a US airstrike on Thursday.