The U.S. State Department has updated travel advisories across the Middle East, warning Americans of heightened threats from Iranian-backed Houthi rebels and suspected Iranian plots targeting U.S. citizens overseas.

The advisories, updated Friday, warn of potential additional attacks by the Houthis, who have previously targeted civilian airports and other critical infrastructure in Saudi Arabia, causing casualties and major travel disruptions. The updates cover Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates and Yemen.

The department did not raise the existing travel advisory levels but revised its warnings to reflect the evolving security situation. The changes come as U.S. intelligence officials report an increase in Iranian efforts to target American personnel abroad, with some suspected assassination plots reaching advanced stages.

According to a memorandum obtained by Axios and The Associated Press, Director of National Intelligence Jay Clayton warned Secretary of State Marco Rubio on Friday that Iranian operations targeting Americans had intensified in the Middle East and other countries.

“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 memorandum did not identify specific targets or provide details about the suspected plots. Clayton urged officials to distribute the intelligence more widely to ensure potentially threatened American personnel were informed of the risks.

In response to the security concerns, the State Department has ordered nonemergency U.S. government employees and their family members to leave Saudi Arabia. The directive applies to personnel assigned to the U.S. Embassy in Riyadh and consulates in Jeddah and Dhahran.

In its Oct. 23 advisory, the department urged Americans to reconsider travel to Saudi Arabia because of the threat of drone and missile attacks against U.S. interests by Iran and the Houthis.

The department is also reducing staffing at diplomatic missions in Jordan, Lebanon, Qatar and the United Arab Emirates, according to The Associated Press. Those missions remain open under restricted operations, but personnel at those four locations have not been ordered to leave.

A U.S. official told Axios that threats from Iranian-backed militants and possible assassination attempts prompted the additional security measures.

“We decided that due to the threat of Houthi attacks and Iranian terror plots we need to reduce our footprint and keep only essential staff,” the official said.

The updated advisories maintain Level 4, or “Do Not Travel,” warnings for Iran, Iraq, Lebanon, Syria and Yemen. Saudi Arabia, Jordan, Bahrain, Kuwait, Oman, Qatar and the United Arab Emirates remain at Level 3, advising Americans to reconsider travel. Israel also remains at Level 3 because of terrorism and civil unrest.

The State Department separately warned of potential risks to commercial aviation as military tensions continue across the region. Americans traveling or living in affected countries are being urged to monitor embassy security alerts, enroll in the Smart Traveler Enrollment Program, and prepare emergency departure plans that do not rely on U.S. government assistance.

The security precautions come as negotiations between Washington and Tehran remain stalled, and President Donald Trump has renewed warnings of possible U.S. military action. American officials have denied that the diplomatic staffing reductions are connected to potential strikes against Iran.

Speaking at a rally in Florida on Friday, Trump said the United States could resume military action if Tehran failed to reach an agreement.

“We may do another little Epic Fury, or they'll agree. If they're smart, they'll just say, 'Let's get down to business,'” Trump said, according to The Associated Press.

Mediators have continued efforts to bring Washington and Tehran back to formal negotiations as American officials assess the risks to U.S. personnel throughout the Middle East.