An Iranian Islamic Revolutionary Guard vessel pointed its weapons at a U.S. Navy helicopter in the Strait of Hormuz on Saturday, two U.S. defense officials told Reuters on Monday, an action they described as “unsafe and unprofessional.”

The officials, speaking on the condition of anonymity, said the incident took place when a Navy SH-60 helicopter flew within half a mile (0.8 km) of two Iranian vessels in international waters. One of the vessels pointed its weapons at the helicopter, the U.S. officials said.

The officials added that at no point did the crew of the helicopter feel threatened, but it was unsafe because it could have lead to an escalation.

Iranian representatives did not immediately respond to a request for comment.