Syria's main Western-backed opposition group on Thursday, Sept 11, welcomed President Barack Obama's authorization of U.S. airstrikes targeting the Islamic State group inside Syria, saying it stands "ready and willing" to partner with the international community to defeat the extremists, the Associated Press reports.

But the Syrian National Coalition said that equally important was the realization that fighting the Islamic State group alone is not enough and should be coupled with degrading and ultimately removing President Bashar Assad's regime.

"The Syrian Coalition ... stands ready and willing to partner with the international community not only to defeat ISIS but also rid the Syrian people of the tyranny of the Assad regime," said the Coalition's chief Hadi Bahra, using one of several acronyms for the Islamic State group. Another common one is ISIL.

In a prime-time address to the nation from the White House, Obama announced he was authorizing U.S. airstrikes inside Syria for the first time, along with expanded strikes in Iraq as part of "a steady, relentless effort" to root out Islamic State extremists and their spreading reign of terror.

He also urged Congress anew to authorize a program to train and arm Syrian rebels who are fighting both the Islamic State militants and Syrian President Bashar Assad.

"We will hunt down terrorists who threaten our country, wherever they are," Obama declared. "That means I will not hesitate to take action against ISIL in Syria, as well as Iraq."

He did not say when U.S. forces would begin striking at targets inside Syria.