Director of National Intelligence Jay Clayton warned Friday that Iran has “substantially increased efforts to target U.S. personnel” abroad, with plots to kill Americans reaching “advanced stages” in the Middle East and other countries.

The warning, contained in an unclassified memo that was sent to Secretary of State Marco Rubio and obtained by CBS News, comes as the State Department , and the U.S. military pares back its footprint in the region, amid concerns about direct threats from Iran and threats from the Iranian-backed Houthi movement in Yemen.

“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, which was issued as the Trump administration weighs resuming military strikes against Iran, does not identify specific targets or countries where the alleged plots are underway, or indicate whether attacks may be imminent. 

Clayton said the U.S. intelligence community is working to downgrade sensitive intelligence — received through various channels — so it can be shared more broadly with State Department personnel. CIA Director John Ratcliffe was copied on the memo.

Axios was first to report on the memo.

The warning follows a series of precautions at U.S. diplomatic facilities across the region. Earlier this week, the State Department ordered non-essential U.S. embassy personnel and their families to depart Saudi Arabia. Several other American embassies in the region adjusted their staffing under “restricted operations” status, which allows them to reduce the number of personnel without formally going on ordered departure, CBS News previously reported.

“When it comes to our staffing at embassies, we constantly evaluate new information about the security environment,” a U.S. official told CBS News on Friday. “The threat of Houthi attacks and of Iranian terror plots targeting U.S. officials are informing our decisions on staffing adjustments for embassies on RO [Restricted Operations] Status in the region.”

A U.S. official and a senior U.S. military official also told CBS News this week that the military has been quietly reducing its footprint at posts in the Middle East due to ongoing threats.

Houthi militants have against Saudi Arabia, targeting oil infrastructure and airports. One strike on Riyadh’s King Khalid Airport earlier this month , including a U.S. citizen, and injured hundreds more.

Last weekend, U.S. embassies in Saudi Arabia, Bahrain, Qatar, the United Arab Emirates and other countries due to Houthi attacks. 

Although the U.S. and Iran have refrained from striking each other in recent weeks, President Trump has not ruled out restarting hostilities after next month’s midterm elections. Iran has also continued to take responsibility for attacks on oil tankers in the Strait of Hormuz.

At a campaign rally in Florida on Friday, Mr. Trump suggested the U.S. could launch another operation against Iran if Tehran failed to reach an agreement.

“We may do another little Epic Fury, or they’ll agree,” the president said, invoking the name of the U.S. military campaign launched in February.