The State Department issued a Worldwide Caution security alert on Saturday afternoon “due to heightened tensions” in the Middle East after the United States and Iran exchanged increasingly heavy fire throughout the week over control of the Strait of Hormuz.

“The security environment remains complex with the potential for unforeseen escalation,” the announcement said. “We remind Americans in the region of the continued need for caution and encourage them to monitor the news for breaking developments. The Department of State advises Americans worldwide, especially in the Middle East, to exercise increased caution.”