US Navy warns vessels in the Middle East to stay away from its warships or risk being seen as a 'threat'

• The US Navy warned vessels in the Middle East to stay at least 100 meters from US warships in a Tuesday notice.
• "Armed vessels approaching within 100 meters of a US naval vessel may be interpreted as a threat and subject to lawful defensive measures," the notice read.
• The warning comes after President Donald Trump said in late April he had ordered the Navy to "destroy" Iranian gunboats that get too close to US ships, an apparent response to an incident last month in which Iranian vessels harassed US Navy and Coast Guard ships in the Persian Gulf.

In a message clearly aimed at Iran, US Naval Forces Central Command, which oversees operations in the Middle East, issued a warning Tuesday ordering foreign vessels to stay away from its warships or risk being seen as a threat.

A Notice to Mariners issued Tuesday said that "due to recent events and in order to enhance safety, minimize ambiguity and reduce opportunities for miscalculation, all vessels are advised to maintain a safe distance of at least 100 meters from US naval vessels in international waters/straits."

"Armed vessels approaching within 100 meters of a US naval vessel may be interpreted as a threat and subject to lawful defensive measures," the notice added.

A defense official told Insider that the Notice to Mariners, which was first reported by Reuters, does not represent a change to the existing rules of engagement, which allow warship captains to exercise the right to self-defense and use lethal force in cases where hostile intent is perceived.

While close approaches, even by countries like Iran, are troubling, they are not normally considered a threat requiring "defensive measures."

The notice follows a tweet by President Donald Trump in late April stating that he instructed the US Navy to "destroy any and all Iranian gunboats if they harass our ships at sea."

"We don't want their gunboats surrounding our boats and traveling around our boats and having a good time," Trump said at a White House press briefing later that day.

"We don't want them anywhere near our boats," he added.

On April 15, nearly a dozen Iranian Islamic Revolutionary Guard Corps (IRGC) gunboats sailed out to harass US Navy and Coast Guard vessels operating in the Persian Gulf, with one of the boats crossing just 10 yards in front of a Coast Guard cutter.

The Iranian vessels did not respond to efforts by the US Navy to communicate with them for about an hour.

"We're not going to stand for it," the president said at the April 22 briefing. "They'll shoot them out of the water," Trump said, referring to US warships firing on Iranian gunboats.

Pentagon leaders said at the time that they interpreted the president's tweet as a warning to Iran, one they welcomed. Gen. John Hyten, the vice chairman of the Joint Chiefs of Staff, said that the Department of Defense would "apply the clear direction from the commander-in-chief into lawful orders that we execute."

He stated US commanders are ready to respond with "overwhelming lethal force" if threatened by Iran.