His message came a day after General Martin Dempsey, chairman of the US Joint Chiefs of Staff, left the door slightly ajar to the possibility of some ground forces during congressional testimony that worried some Democrats.
"As your commander in chief I will not commit you and the rest of our armed forces to fighting another ground war in Iraq," Obama said.
Iraq's new prime minister said earlier on the same day that foreign ground troops were neither needed nor welcome on his country's soil. In his first interview with foreign media since taking office on September 8, Haider al-Abbadi told the Associated Press news agency that US airstrikes have helped Iraq's efforts to deter IS, but said foreign boots on the ground were "out of the question."
"Not only is it not necessary," he said, "We don't want them. We won't allow them. Full stop." Dempsey had said that he might recommend having US troops do more, potentially accompanying Iraqis during complicated offensives, such as a battle to retake the northern city of Mosul from IS fighters. "It could very well be part of that particular mission - to provide close combat advising or accompanying for that mission," he said.
Dempsey acknowledged that Obama's "stated policy is that we will not have US ground forces in direct combat.
Iraq's Al-Abadi, though ruling out ground troops, urged the international community to expand its campaign against IS to include neighbouring Syria.
"The fight will go on unless ISIL is hit in Syria," he said. "This is the responsibility of the international community - on top of them the United States government - to do something about ISIL in Syria," al-Abadi said. "We cannot afford to fight our neighbour, even if we disagree on many things," al-Abadi said. "This is our neighbour. We don't want to enter into problems with them. For us sovereignty of Syria is very important."
IS was established in Iraq but spread to Syria, where years of civil war laid the ground for it to grow exponentially.
Following its success in Syria, the group's fighters - including many Iraqi nationals - took over northern and western Iraq in June, seizing control of a huge swath of territory. The group now rules over land stretching from northern Syria to the outskirts of Baghdad.