President Trump said the troops will have a "mostly protective" role (Picture: US Department of Defense).
The US is set to bolster its military presence in the Middle East with an additional 1,500 troops amid rising tensions with Iran.
President Donald Trump told reporters outside the White House the troops would have a "mostly protective" role.
Congress had been notified about the move earlier in the day.
According to a copy of the notification obtained by the Associated Press, "roughly" 1,500 soldiers will deploy in the coming weeks, "with their primary responsibilities and activities being defensive in nature".
It also said how their mission will include protecting US forces already in the region and ensuring the freedom of navigation.
Iran's Foreign Minister condemned the announcement, saying the increase of troops to the Middle East is "extremely dangerous" to "international peace and security".
Meanwhile, an Iranian military official told the Mizan news agency that they could "send these ships [US] to the bottom of the sea along with their crew and planes using two missiles or two new secret weapons".
The US has been strengthening its military presence in the Middle East in response to what it said was a threat from Iran, with President Trump labelling Tehran "the number one provocateur of terror".
Earlier this month, the US sent an aircraft carrier and bombers to the Persian Gulf to counter supposed Iranian threats.
The US already has tens of thousands of troops in the Middle East, including at a major Navy base in Bahrain and an Air Force base and operations centre in Qatar.