The USS Mahan, a U.S. Navy destroyer nicknamed "built to fight," fired three warning shots Sunday toward four Iranian vessels in the Strait of Hormuz, a politically strategic and often disputed strait between the Gulf of Oman and the Persian Gulf. The incident was spurred after the four Islamic Revolutionary Guard Corps ships sped toward the Navy warship, seemingly out of nowhere, while failing to respond to U.S. officials repeated requests for them to slow down, Reuters reported Monday morning.

The USS Mahan fired its three warning shots toward the Iranian vessels after the four ships came within 900 yards. The Navy was attempting to make contact with the Iranian vessels after they began encroaching on the U.S. warship at an atypical rate, Reuters reported. Iran’s Islamic Revolutionary Guard Corps responded to the Navy’s radio communication, but would not adhere to requests for the vessels to stop speeding toward the destroyer. A U.S. Navy helicopter responded by dropping a smoke float as the USS Mahan began firing warning flares, all while the four ships reportedly continued asking questions to U.S. officials.

As of Monday morning, it remained unclear exactly what communication transpired between the two nation’s vessels before the USS Mahan fired three warning shots toward Iran’s ships. Multiple officials spoke on conditions on anonymity, noting the U.S. destroyer was escorting two other U.S. military ships at the time of the incident, Reuters reported. 

The news arrived as the future of U.S.-Iranian relations remain unclear, with Iran recently warning President-elect Donald Trump not to toss the nuclear deal President Barack Obama’s White House administration spearheaded in 2015.

Trump’s strong rhetoric against similar incidents by Iran’s Islamic Revolutionary Guard could indicate a tougher response from U.S. ships like the USS Mahan under the next White House administration. The president-elect vowed that any Iranian ship harassing U.S. Navy vessels would be "shot out of the water" during a campaign rally in September. 

"(Trump) wants to do many things, but none of his actions would affect us," Iranian President Hassan Rouhani said in December, vowing to prevent any obstruction to the current policy by the next U.S. president. "By capitalizing on the dispute over Iran's nuclear issue, they want to persuade others that the Islamic Republic establishes a threat against security and stability of its neighbors as well as Europe and the global peace."

This isn’t the first time a close encounter between the nations’ vessels prompted warning shots. A U.S. Navy patrol vessel fired three warning blasts toward a single Iranian boat when it began reportedly intimidating the craft, coming within just 200 yards of the ship in August. Three warning fires are the official maritime standard response to apparent conflict in the region.