"I think we have a president who just doesn't know what he's doing," Trump told CNN on Saturday. "You either do it or you don't do it. Fifty people. He puts 50 people."
Trump did not say whether he would deploy more troops to Syria as president, but simply said, "You either do it or you don't do it."
The remarks are the first time Trump has reacted to Obama's decision to deploy fewer than 50 Special Operations forces to Syria, which the White House announced Friday. The announcement came two years after Obama addressed the American public and said emphatically: "I will not put American boots on the ground in Syria."
Trump spoke briefly with CNN on Saturday as he arrived at a campaign rally in Norfolk, Virginia, where his podium is stationed in front of the USS Wisconsin.
Trump, along with other 2016 GOP contenders, has been highly critical of Obama's handling of the war against ISIL.
Trump has said that he would deploy American troops back to Iraq to combat ISIL but has argued against deepening US involvement in Syria.
Instead, Trump has said that he would be in favor of allowing Russian President Vladimir Putin to continue his bombing campaign in the country, which has been met with objection by Washington.