The announcement comes a day after a marine was killed and several others were hurt in an IS rocket attack on an Iraqi base.
A detachment of US marines has been deployed on the ground in Iraq to support operations against Islamic State, the American military has said.
The troops from the 26th Marine Expeditionary Unit, or MEU, will add to the American forces already in the country battling the jihadist terror group.
The 26th MEU is currently deployed in the US 5th Fleet area of operations, which covers the Gulf, Red Sea, Arabian Sea, and parts of the Indian Ocean.
On Saturday, a US marine was killed and several others were wounded at a northern Iraqi base after it was targeted in a rocket attack by IS militants near Makhmur.
It is a district around 45 miles southeast of the main IS stronghold of Mosul and 170 miles north of the Iraqi capital Baghdad.
And it lies within territory controlled by the autonomous northern region of Kurdistan.
But the Iraqi government has recently been deploying federal forces there to prepare for an offensive against Mosul.
It was the second combat death of an American service member in Iraq since the US military campaign against IS started in summer 2014.
The US and its coalition’s main role has been to provide air support, with close to 10,000 strikes destroying or damaging more than 16,000 targets.
The last American soldier to be killed in combat in the country was Master Sergeant Joshua Wheeler, 39, who died in October.
Master Sergeant Wheeler, a Special Forces member from Roland, Oklahoma, was killed in a raid that freed 70 IS hostages from a makeshift prison in northern Iraq.
He was the first soldier to die in combat in Iraq since 2011 when US forces withdrew after more than eight years of operations in the country.
Around 3,700 US troops are now on the ground in Iraq advising the country’s army.