The actions were the latest by the Trump administration as it highlights what it sees as a threat of potential attack by Iran, and follows decisions to speed the deployment of an aircraft carrier strike group as well as send bombers and additional Patriot missiles to the Middle East.
"This is a prudent response to credible threats from Iran", said Acting Defence Secretary Patrick Shanahan. It also includes a fighter jet squadron.
The administration notified Congress earlier in the day about the troop plans.
There's also evidence of small modified fishing boats "capable of launching cruise missiles", he said.
A top USA official has accused Iran directly of attacking oil tankers.
USA officials said the meeting persuaded Trump to approve a relatively modest increase in the number of United States forces stationed in the region.
"I don't think we're going to need them", he told reporters.
"It may involve sending additional troops", he said.
What is the latest USA move? Shanahan he said his focus right now is determining "the right force protection" in the region.
Still, the Democratic lawmaker who heads the House Armed Services Committee, Adam Smith, said the deployment "appears to be a blatant and heavy-handed move to further escalate tensions with Iran".
Kylian Mbappe Drops Huge Hint At Move Away From PSG
Mbappe has been linked with a possible move to Real Madrid , where Zinedine Zidane returned as coach earlier this season. "If it's at PSG , it's good, if it's elsewhere, it will be elsewhere for a new challenge".
The deployment represents "a prudent defensive measure and meant to reduce the possibility of future hostilities", with Tehran and its regional allies, he added. Shanahan reportedly briefed President Donald Trump on new military options Thursday night.
"When I first got here, they were in 14 different locations fighting", he said.
"There is no 10,000, and there is no 5,000". Iran has dismissed the accusations entirely and accuses the United States of brinkmanship with its troop deployments.
The Pentagon said only about 900 of the 1,500 troops will be newly deploying and that 600 are already in the region and will be extended.
What is behind the tensions?
Trump withdrew from the 2015 nuclear deal between Iran and six major powers a year ago and now is seeking to block all Iranian oil exports.
A number of deals to Saudi Arabia and the United Arab Emirates have been on hold in the Senate over concerns about how the countries are prosecuting their controversial conflict against the Iranian-backed Houthi rebels in Yemen, as well as over Saudi Arabia's brutal murder of journalist Jamal Khashoggi.
Washington believes a series of recent attacks in the region may have been inspired by Iran, including a rocket attack in Baghdad's heavily fortified Green Zone. Iran has denied involvement in the incidents.
"The attack against the shipping in Fujairah we attribute it to the IRGC", said Rear Admiral Michael Gilday, a director of the Joint Staff, adding that the Pentagon attributed limpet mines used in the attack to the IRGC.