Word of the exercise follows Monday's announcement that a second U.S. aircraft carrier will be sent to the region in September -- several months earlier than planned -- to ensure there will be two carriers in the region through early next year. The Pentagon also recently doubled the number of minesweepers in the region. And it sent the USS Ponce, an amphibious transport dock recently retrofitted to become what is known as an afloat forward staging base.

The buildup comes amid a stalemate in talks over Iran's nuclear program, which Tehran says is for peaceful purposes and other nations fear is to develop a nuclear weapon.

The exercise will practice mine countermeasures in multiple waterways. It will demonstrate "the international community's ability to work together to ensure free and secure trade," said Gen. James Mattis, commander for the region.

"Of the approximately 40 bilateral and