Obama's decision to launch attacks inside Syria, which is embroiled in a three-year civil war, marked a turnabout for the president, who shied away a year ago from striking the Syrian government stances under the pretext of using chemical weapons, a claim which was never proved.

In a widely anticipated, 13-minute White House speech, Obama said he would hunt down ISIL terrorists "wherever they are" in a drive to degrade and ultimately destroy the terrorist group, which was reportedly organized and initially trained by the US in Jordan.

"That means I will not hesitate to take action against ISIL in Syria, as well as Iraq. This is a core principle of my presidency: if you threaten America, you will find no safe haven," he said.

Obama also asked Congress to authorize $500 million to train and arm some other Syrian rebels. The training would take place in Saudi Arabia. It is unclear whether more American weapons and training can shift the battlefield balance toward the U.S.-backed rebels.

A vote on the money would put lawmakers on record supporting the military action, although White House officials stressed Obama already had the authority he needed for the new moves.

Obama plans to expand the list of targets inside Iraq beyond several isolated areas. The new target list will include ISIL terrorist group’s "leadership, logistical and operational capability," as well as an attempt to "deny it sanctuary and resources to plan, prepare and execute attacks," the White House said.

U.S. officials have warned it will take years to destroy ISIL terrorist group, and Obama told Americans: "It will take time to eradicate a cancer like ISIL," the White House's acronym for the militant group.

Obama will send 475 more American advisers to help Iraqi forces, which will bring to 1,600 the number here.

NJF/NJF