Here's what it looked like when 2 Iranian speedboats zipped by a US warship carrying the top commander in the Middle East

• The US Navy had a close encounter with Iranian boats in the Persian Gulf last week.
• Two Iranian speedboats zoomed by a US warship while the head of US Central Command was onboard.
• Iran and the US have a long history of such run-ins, though this was was deemed safe and professional.

Two Iranian fast boats zoomed by the amphibious assault ship USS Essex on Friday, passing by within 300 yards of the ship while Army Gen. Joseph Votel, the head of US Central Command, was on board.

Iran's Revolutionary Guard Corps navy has a history of close and often provocative encounters with the US Navy operating in the Persian Gulf and surrounding waters.

Capt. Brian Muttay, the Essex's commander, told NBC News that the encounter was "annoying," but it was not "unsafe and unprofessional," Navy officials said Friday, nor did it appear related to the visit by Votel, who oversees US forces in the Middle East.

Videos of the incident published by The Washington Post and Associated Press correspondent Lolita Baldor showed the fast boats zipping by within eyesight of the Essex, the largest US ship operating in the area at the time.

Iranian boats performed similar maneuvers around the Essex and the ships accompanying it regularly, sometimes several times a week, Navy officials told The Post. On Friday, a total of six Iranian vessels approached the Essex's amphibious ready group.

Mutty told NBC News that earlier on Friday, an Iranian sailor warned the Essex that Iranian boats would shoot at a US helicopter operating from the Essex if it continued to fly around their boats. The helicopter continued operations, however, and no shots were fired.

Votel, speaking aboard the Essex, told reporters that the ship's crew reacted in a way that lowered the risk of the encounter escalating. He said it was typical for Iranian boats to maneuver within one-quarter of a mile of US ships.

"Iran is always a concern, and so we will be vigilant as we always are, not just here in the maritime environment but really across the theater," Votel said. "Because we have to be."

Encounters the US declared to be unsafe or unprofessional were relatively common during the final months of the Obama administration. In some cases, the US ships would fire warning shots.

Such incidents have dropped off during the Trump administration, with the last "unsafe and unprofessional" encounter taking place on August 14, 2017, when an Iranian drone without any navigation lights flew close to aircraft conducting night-landing operations on the US aircraft carrier Nimitz.

Votel said the boats' actions were typical and that Iranian vessels in the area were usually "shadowing" US ships.

Capt. Gerald Olin, who leads the Essex's amphibious ready group, said the Iranians were trying to gather information on US naval operations, recording the ships on camera. Olin told The Post his ships used loudspeakers to communicate with the Iranian boats.

While there have not been any unsafe or unprofessional encounters since then, Iranian drones are increasingly active around US ships in the area.

The Navy says it has not "adjusted its operations" and will operate wherever international law allows, but the conduct of Iranian drones has been a source of concern.

"Even with decreased incidents, we remain concerned with the increased number of Iranian UAVs operating in international airspace at night without navigation lights or an active transponder as would be expected according to international norms," Lt. Chloe Morgan, a US Naval Forces Central Command spokeswoman, told Business Insider earlier this month.