Director of National Intelligence Jay Clayton warned in an unclassified memo sent Friday to Secretary of State Marco Rubio that Iran has "substantially increased efforts to target U.S. personnel" abroad. "The lethal plotting efforts by the Iranians against U.S. citizens have reached advanced stages in both the Middle East and certain other countries," Clayton wrote. The memo, first reported by Axios and obtained by CBS News, the BBC and The Associated Press, does not identify specific targets or countries, nor does it say whether attacks are imminent. CIA Director John Ratcliffe was copied on the document.

The warning came as the State Department adjusted staffing across the region. Earlier this week it ordered nonessential personnel and their families to leave Saudi Arabia, and it announced reduced staffing at the embassies in Jordan, Lebanon, Qatar and the United Arab Emirates, all of which already operate under "restricted operations" status. Staff at those four posts are not compelled to leave, and the embassies remain open. Three U.S. officials told the AP that the threats from Iran and from Yemen's Iranian-backed Houthi rebels are related to the staffing changes, though the State Department's public announcement cited only the Houthi threat. Clayton said intelligence agencies are working to downgrade sensitive intelligence so Rubio can share more of it with State Department personnel. A U.S. official and a senior military official also told CBS News the military has been quietly reducing its footprint at some regional posts.

The Houthis have escalated drone and missile attacks on Saudi Arabia since an informal four-year ceasefire began unraveling in July, when the group announced a "maritime embargo" against the kingdom. A missile strike on Riyadh's King Khalid International Airport on October 10 killed 13 people, including a U.S. citizen, and injured 308, making it the deadliest attack in Saudi Arabia in more than a decade. Saudi authorities say at least 21 people have died in Houthi attacks on the country's airports since the start of October. The Houthis say the attacks respond to a Saudi blockade of ports and airports in their territory and an airstrike on Sanaa airport they attribute to the kingdom. U.S. embassies in Saudi Arabia, Bahrain, Qatar and the UAE issued cautionary alerts to Americans last weekend.

The developments follow a wider war in the region. The United States and Israel launched an air campaign against Iran in February, killing its leader, and Tehran retaliated with strikes on U.S. allies and effectively closed the Strait of Hormuz, through which about a fifth of the world's oil and gas normally passes. A preliminary agreement reached in June to end the war and reopen the strait collapsed within weeks after Iranian attacks on shipping resumed and the U.S. reinstated its blockade. The war has raised energy costs for Americans and created political difficulties for President Donald Trump and Republicans ahead of the November 3 midterm elections.

The U.S. and Iran have refrained from striking each other in recent weeks, but the administration is weighing whether to resume strikes. Speaking at a rally in Florida on Friday, Trump said, "we may do another little Epic Fury, or they'll agree," referring to the name of the U.S. operations against Iran. U.S. officials have denied that the embassy drawdowns are tied to potential new strikes. Mediators continue to try to return the two sides to formal talks, while Iranian state television reported that the Revolutionary Guard navy again threatened to strike U.S. bases in the region if the United States continues helping guide commercial vessels through the Strait of Hormuz.