The additional troops from the 82nd Airborne Division will be deployed to Iraq, Kuwait and other parts of the region, Xinhua news agency quoted an NBC News report as saying on Friday.
The soldiers will join roughly 650 others already deployed to the region and remain for some 60 days, NBC News said in the report citing US officials as saying.
"As previously announced, the Immediate Response Force (IRF) brigade of the 82nd Airborne Division was alerted to prepare for deployment, and are now being deployed," the Pentagon said in a statement.
"The brigade will deploy to Kuwait as an appropriate and precautionary action in response to increased threat levels against US personnel and facilities, and will assist in reconstituting the reserve."
The latest move by the Pentagon came just hours after Soleimani, the commander of Iran's Islamic Revolution Guards Corps Quds Force, and Iraqi militia commander Abu Mahdi al-Muhandis were killed an airstrike near the Baghdad International Airport.
Iran's Supreme Leader Ayatollah Ali Khamenei and President Hassan Rouhani have vowed to retaliate strongly against the US over the Major General's death.
Friday's attack came after Iraqi protesters on Tuesday stormed the US embassy compound in Baghdad to protest the American air raids conducted on December 29 against five bases of Iran-backed militias in Iraq and Syria, claiming the lives of 25 people.
( With inputs from IANS )