The UNHCR noted that it was closely monitoring the situation in Iran where it maintained presence over four decades ago.
The refinery processes about 550,000 barrels of oil per day, making it one of the largest refining and export hubs in Saudi Arabia.
Crucial territories along the Iran-Iraq border are dominated by Kurdish troops in northern Iraq.
“The Israelis just struck the meeting of the Iranian Supreme Council where officials were gathering to choose a new Supreme Leader, Mr Yingst said.
The U.S. government asked citizens to remain alert and seek refuge at bomb shelters.
The State Department made the decision on Tuesday after the embassy in Riyadh was targeted by two Iranian drones late Monday night.
Mr Trump previously declined to attend, criticising media coverage of his presidency as “extraordinarily bad.”
The IRGC also claimed that a U.S. combat support vessel sustained heavy damage.
Authorities said both central and provincial election committees would publicise the official results nationwide to ensure transparency.
Ukrainian forces said on Tuesday that they struck a major oil terminal and a naval base in Russia’s southern port city of Novorossiysk.
