The US has released images it says shows Iran was behind recent attacks in the Gulf of Oman (Picture: Pentagon).
The United States says it will send about 1,000 additional troops to the Middle East.
The acting US Secretary Of Defense Patrick Shanahan said the deployment was for defensive purposes to address air, naval and ground-based threats.
The Pentagon has released new photographs which it says provide further evidence that Iran is to blame for the attacks on two tankers.
Iran has denied any involvement in the attacks, with President Hassan Rouhani stating his country is not seeking to "wage war with any nation".
On Friday, the US military released video which it said showed Iran's military removing an unexploded mine from one of the two oil tankers attacked in the Gulf of Oman.
The additional troops being sent to the Middle East by the United States are part of a broader military package of options that were initially laid out to American leaders late last month, totaling 10,000 forces, Patriot missile batteries, aircraft and ships.
In announcing the deployment, acting US Defence Secretary Patrick Shanahan said the forces are "for defensive purposes to address air, naval, and ground-based threats in the Middle East."
"The United States does not seek conflict with Iran," Mr Shanahan said.
"The action today is being taken to ensure the safety and welfare of our military personnel working throughout the region and to protect our national interests."
He added that the US will continue to adjust troop levels as needed.