Some 20 to 30 special operators will comprise the first US troops on the ground in the war-torn country, Reuters reported, citing US officials.
The White House is expected to announce the decision later on Friday.
The move marks a shift in strategy for the Obama administration after previous attempts to train and equip moderate rebels in the region failed to achieve success.
Pentagon chief Ash Carter signalled to members of Congress on Tuesday the administration was considering an escalation of military action against IS in Iraq and Syria.
He said: "We won't hold back from supporting capable partners in opportunistic attacks against ISIL, or conducting missions directly, whether by strikes from the air or direct action on the ground."
As part of the revised strategy, President Obama also authorised the deployment of A-10s and F-15s to Incirlik air base in Turkey, the official told Reuters.
Source: Bloom Gist and Agencies
