"Just as I approved additional support for Iraqi forces against ISIL, I've decided to increase U.S. support for local forces fighting ISIL in Syria, a small number of special operations forces are already on the ground in Syria and their expertise has been critical as local forces have driven ISIL out of key areas," Obama said, using another acronym for the jihadist group.
"So given their success I've approved the deployment of up to 250 additional U.S. personnel in Syria including special forces to keep up this momentum," he said.
Obama stressed that U.S. troops will not be leading the fight on the ground but they will be essential in training and assisting local forces.
"So make no mistake these terrorists will learn the same lesson as others before them have, which is 'your hatred is no match for our nations united in the defense of our way of life,' " he said, adding that the increase would bring the number of U.S. special forces in the country to as many as 300 troops, including special forces.
But the President said he would continue to pursue diplomatic solutions to ending the Syrian civil war.
"Just as we remain relentless on the military front we're not going to give up on diplomacy to end the civil war in Syria because the suffering of the people in Syria has to end and that requires an effective political transition," he said.
Supporting Syrian allies
The troops will be expanding the ongoing U.S. effort to bring more Syrian Arab fighters into units the U.S. supports in northern Syria that have largely been manned by the Kurds, an official told CNN earlier.
The plan calls for the additional U.S. forces to "advise and assist" forces in the area whom the U.S. hopes may eventually grow strong enough to take back territory around Raqqa, Syria, where ISIS is based.
These troops are not expected to engage in combat operations or to participate in target-to-kill teams but will be armed to defend themselves, one official said.
"As we have noted in recent days, the President has authorized a series of steps to increase support for our partners in the region, including Iraqi security forces as well as local Syrian forces who are taking the fight to ISIL," a senior administration official CNN. "The President during his remarks at the Hannover Messe fairgrounds on Monday will speak to this additional step."
The official said the President was persuaded to take this additional step because of recent successes against ISIS.
CNN first reported details
of the expected plan several weeks ago.