The U.S. Department of State issued a global security alert on Sunday, advising Americans worldwide to stay vigilant against potential threats from groups linked to Iran.

“The Department of State encourages Americans, particularly those in the Middle East, to exercise heightened caution. Individuals abroad should adhere to security advisories provided by the nearest U.S. embassy or consulate,” the statement read.

The warning also mentioned, “Occasional airspace closures might lead to travel disruptions. U.S. diplomatic facilities, even beyond the Middle East, have been targeted.”

The alert further noted, “Groups allied with Iran may aim at other U.S. interests or locations associated with the United States and Americans globally.”

This alert was issued shortly after a stark warning from Iranian military spokesman Gen. Abolfazl Shekarchi on Friday, who stated that Tehran’s militants would now target popular tourist destinations amid ongoing U.S. and Israeli attacks on Iran.

Tensions have intensified across the Middle East following the U.S. and Israeli bombings in Iran on February 28, which resulted in the death of Supreme Leader Ali Khamenei.

Iran quickly hurled retaliatory rockets at American interests in the region, with missiles hitting tourist hubs in Dubai and Israel.

A projectile struck the US Embassy in Baghdad last Friday night, hitting a helipad on the sprawling compound that Iranian-backed militants have repeatedly targeted since the conflict in the Middle East began.

Iran on Sunday also vowed to deploy a policy of “zero restraint” and hit energy infrastructure across the Persian Gulf as well as banks that do business with the US if President Trump carries out his threat to “obliterate” Tehran’s power plants.

Trump’s ultimatum demanded an end to the Islamic Republic’s hostilities in the Strait of Hormuz, a key trade route that oversees the flow of 20% of the world’s oil supply. The president set a 48-hour deadline for the deal, which ends around 8 p.m. ET on Monday.

Iran’s Parliament Speaker Mohammad ⁠Baqher Qalibaf said his country would make no such concession, warning of a retaliatory attack that would ramp up already-high energy costs across the world if Trump follows through with the blitz.