US and UK navy ships are seen conducting Mine Countermeasures Exercise (MCMEX) taking place at Arabian Sea, September 10, 2018. Image used for illustrative purpose.

U.S. Navy Mark VI Patrol Boat makes its way towards an exercise area during a U.S./UK Mine Countermeasures Exercise (MCMEX) taking place in Arabian Sea, September 11, 2018. REUTERS/Hamad I Mohammed

U.S. Navy MH-53E Sea Dragon helicopters are seen making their way to an exercise area as they take part in a U.S. and U.K. Mine Countermeasures Exercise (MCMEX) taking place at the Arabian Sea, as a cargo ship is seen sailing towards Straits of Harmoz, September 10, 2018.

A U.S. Navy soldier onboard Mark VI Patrol Boat stands guard as an oil tanker makes its way towards Bahrain port, during an exercise of U.S./UK Mine Countermeasures (MCMEX) taking place in Arabian Sea, Bahrain September 11, 2018. Image for illustrative purposes.

A U.S. Navy ground technician inspects the sonar object detector on an MH-53E Sea Dragon helicopter at the U.S. Naval air-support unit in Bahrain, prior to its flight to take part in a U.S. and U.K. Mine Countermeasures Exercise (MCMEX) taking place at the Arabian Sea, September 10, 2018.

A U.S. Navy MH-53E Sea Dragon helicopter flies over U.S. and U.K. Navy ships during a U.S. and U.K. Mine Countermeasures Exercise (MCMEX) taking place at the Arabian Sea, September 10, 2018. Image used for illustrative purpose.

U.S. Navy personnel onboard Mark VI Patrol Boat, deploy a sonar detector in the sea during a U.S./UK Mine Countermeasures Exercise (MCMEX) taking place in Arabian Sea, September 11, 2018.

A U.S. Navy soldier onboard Mark VI Patrol Boat stands guard as a tanker makes its way towards Bahrain port, during an exercise of U.S./UK Mine Countermeasures (MCMEX) taking place in Arabian Sea, Bahrain September 11, 2018. Image used for illustrative purpose.