The US is training Gulf allies to "protect navigation" in the region's troubled waterways, as it seeks to build an alliance to contain Iran.
Washington's three-week International Maritime Exercise (IMX), which started on October 21st, came after a number of commercial vessels were attacked in the Gulf from May, ratcheting up regional tensions.
Washington and other Western powers blamed the incidents on Iran, which has denied any involvement.
On Tuesday (November 5th), the US invited international media to see part of the IMX, the second-largest maritime exercise of its kind.
The manoeuvres involve 5,000 personnel, 40 vessels and 17 aircrafts from 50 countries deployed to the strategic waterway that separates Iran from the Gulf states.
"This is the first time we are taking part in the IMX," the head of a Saudi naval de-mining team, Ali Bin Shreidi, said aboard the Cardigan Bay, a British Royal Fleet Auxillary landing ship 65 kilometres off Bahrain's coast.
The officer and his three-member team were taking part in order "to increase our capabilities and share our expertise in fighting mines, in order to protect navigation", he said.
In June, the US Navy alleged that a mine resembling Iranian weaponry was used in an attack on the Japanese-owned Kokuka Courageous tanker, targeted as it passed through the Gulf of Oman.
Then in July, Iran's Islamic Revolutionary Guard Corps (IRGC) seized a British-flagged oil tanker, holding it for more than two months before releasing it.
"One of the biggest reasons for us being out here is to build international relations," said US Navy Lt. Jonathan Phares who was among 300 personnel from the US, France and the Gulf on the Cardigan Bay.
Those aboard showed off diving gear, underwater imaging kit and speed boats during a tour of the gun-metal grey vessel, while others demonstrated mine detection equipment.
In response to the string of incidents in the region's vital shipping routes, the US formed a naval coalition to protect navigation in a waterway that is critical to global oil supplies.
Bahrain, which hosts the US Navy's Fifth Fleet, joined the US-led naval coalition in August. Saudi Arabia and the UAE followed suit in September.
The UK and Australia also have agreed to send warships to escort commercial shipping in the Gulf.
On September 14th, two Saudi oil facilities were attacked, causing catastrophic damage and temporarily knocking out half of the kingdom's oil production.
The attacks were claimed by Yemen's Iran-backed Houthis (Ansarallah), but Washington and Riyadh blamed Iran, saying the strikes were carried out with advanced missiles and drones.