They will also offer aviation support and provide force protection, Carter said, during an unannounced visit to Iraq.
The U.S. will additionally provide Army Apache attack helicopters -- something the U.S. had been pushing for months in the face of resistance from the Iraqi government.
The new forces, which will raise the U.S. troop presence in Iraq to more than 4,000, will be allowed to advise at the battalion and brigade level, rather than be restricted to the division level, Carter said, which means they are closer to the front lines and at greater risk.
Both the troops and the Apaches are expected to play a role in the upcoming offensive by Iraqi security forces to retake Mosul, Iraq's second-largest city, from ISIS.
Carter is holding a series of meetings in Iraq, including with Prime Minister Haider al-Abadi and top U.S. military commanders. Carter is also hosting a question-and-answer session with troops stationed in the country. This is Carter's third visit to Iraq.
An official traveling with Carter said the U.S. is going to bring in more resources into the country and is going to accept more risk in the coming days in Iraq.
The official framed the fight for Iraq as centered around efforts to recapture the northern city of Mosul
from ISIS forces, Iraq's second-largest.
Mosul fell to ISIS after the Iraqi Army abandoned their positions and fled in the summer of 2014.
The comments seemed to complement those made by
Chairman of the Joint Chiefs Gen. Joseph Dunford, the country's top military officer, who said in March that he believes the U.S. will soon increase the number of American troops in Iraq.
"(Carter) and I both believe that there will be an increase to the U.S. forces in Iraq in the coming weeks," he said late last month.
Dunford added that, at the time, a final decision on any troop deployments had yet to be made.
"Taking Mosul will require more fighters than the Iraqi security forces have and those new forces have to be trained," thereby requiring the additional U.S. presence, Nick Heras, of the Center for a New American Security told CNN.
More recently, the U.S. deployed tactical aircraft
capable of attacking ISIS's ability to communicate closer to the front lines of the battle.
The U.S. European Command announced a squadron of Marine Corps EA-6B Prowler aircraft has been sent to Incirlik Air Base in Turkey to support operations against ISIS.
In addition to being able to intercept communications by ISIS, the Prowler can protect allied forces on the ground and strike aircraft by jamming any radar and communication devices ISIS has.