U.S. Secretary of State Mike Pompeo skipped a Monday trip to Moscow to discuss unspecified threats emanating from Iran with European allies, according to the State Department.
Pompeo was scheduled to visit U.S. embassy staffers in Moscow before meeting Tuesday with Russian President Vladimir Putin in Sochi, which is expected to continue as scheduled.
But State Department spokeswoman Morgan Ortagus said Pompeo will instead stop in Brussels "to discuss recent threatening actions and statements by the Islamic Republic of Iran.
"Secretary Pompeo will continue to coordinate closely with our allies and partners to ensure the security of our mutual interests in the Middle East and around the world," Ortagus added.
The Trump administration has for more than a week raised the alarm about threats from Iran, but has refused to elaborate on specifics.
Amid the heightened tensions, Saudi Arabia, Iran's regional rival, said Monday two oil tankers were hit by a sabotage attack off the coast of the United Arab Emirates (UAE).
There was no immediate comment from UAE authorities on the reported attack, but it comes one day after the UAE said four commercial ships were hit by sabotage attacks off the coast of the port city of Fujairah.
The UAE did not give details about the nature of the sabotage or who was behind it.
The port of Fujairah is about 85 miles south of the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a third of all oil at sea is traded.
By Michael Hernandez in Washington