On Monday, Iranian-backed Houthi rebels off the coast of Yemen launched an attack on a Saudi Arabian naval vessel using suicide boats, or fast attack craft laden with explosives.
According to Fordham University maritime law professor and former US Navy Commander Lawrence Brennan, "this attack is likely to impact US naval operations and rules of engagement (ROE) in nearby waters."
The year 2016 saw an unprecedented spike in the number of incidents at sea between the US Navy and fast-attack craft of the Iran's Islamic Revolutionary Guard Corps (IRGC), at least one of which required the US Navy to open fire with warning shots.
Meanwhile, Iranian-backed Houthi rebels in Yemen had a blockbuster year in 2016, using an anti-ship missile to hit an Emirati naval vessel and then firing a salvo of missiles at US Navy ships in October.
The US Navy successfully fended off the Houthi missile attack and retaliated by destroying three radar sites in Houthi-controlled Yemen. At the time, US officials and experts contacted by Business Insider concluded that Iran likely supplied the missiles to the Houthis.
But the latest attack on the Saudis may give the US Navy pause in the future.
In a questionable video released of the attack, people near the camera can be heard shouting slogans like "death to America," "death to Israel," and "death to Jews!" One Pentagon official told the Washington Examiner that the Houthis may have mistaken the Saudi ship they attacked for a US Navy ship, though another official denied it.
In any case, the US Navy frequently deals with Iranian fast-attack craft swarming its vessels and approaching very closely. In one case last year, Iranian fast-attack craft got within 300 yards of a US Navy vessel.
Iranian fast-attack boats during a naval exercise in 2015. | Wikimedia photo by Sayyed Shahaboddin Vajedi
At the time, the US Navy responded by attempting to contact the Iranians, maneuvering evasively, blowing the horn, then finally firing warning shots.
But according to Brennan, the US may not allow hostile, unresponsive ships to get so close to Navy vessels after a force associated with Iran used suicide boats to kill two Saudi sailors.
"The overarching duty of self-defense mandates revision of the ROE to provide a sufficient 'bubble' to prevent the risk of a suicide attack, particularly from swarming boats," said Brennan in an email to Business Insider.
Knowing what they do about suicide boats, should the US Navy allow hostile craft to get within a 300 yard "bubble" of their ships? | US Navy photo by Mass Communication Specialist 2nd Class Brian Caracci
President Donald Trump has already signaled his intention to respond more forcefully.
"With Iran," Trump said while campaigning in Florida, "when they circle our beautiful destroyers with their little boats, and they make gestures at our people that they shouldn't be allowed to make, they will be shot out of the water."