"As mines threaten maritime traffic indiscriminately, the US, France and United Kingdom are dedicated to conducting tactical training to counter the risk of mines in order to support the continued free flow of commerce and freedom of navigation in this critical region," said the US Fifth Fleet, which is based in Bahrain.

The exercise is "purely defensive", Lieutenant Chloe Morgan, a spokesperson for the US Navy, told AFP.

The small kingdom of Bahrain, allied with Gulf powerhouse Saudi Arabia, is located in the waters between the ingdom and its arch-nemesis Iran.

The archipelago is also home to a permanent British military base.