Obama: Syria strikes coalition shows US not 'alone' in fighting IS

President Barack Obama said Tuesday the coalition of Arab nations involved in the first US air strikes in Syria, showed the United States was not alone in combating the Islamic State group.

Obama also warned after US bombing and missile strikes supported by Saudi Arabia, Bahrain, the UAE, Qatar and Jordan that the operation against IS would take time but he would "do what is necessary" to defeat the group.

The president praised the bravery of US pilots who carried out the air strikes in Syria, and also highlighted simultaneous US raids against an Al-Qaeda group that US officials said was plotting attacks on US and Western targets.

"The strength of this coalition makes it clear to the world that this is not America's fight alone," Obama said, speaking in the White House Rose Garden, against the backdrop of his green Marine One helicopter.

"Above all, the people and governments in the Middle East are rejecting ISIL and standing up for the peace and security that the people and the region of the world deserve," Obama said, using an alternative name for the IS group.

The president said that US attacks on the Khorasan group in Syria, which he said was made up of "seasoned" Al-Qaeda operatives sent a blunt message of US intent.

"It must be clear to anyone who would plot against America and try to do Americans harm that we will not tolerate safe havens for terrorists who threaten our people," Obama said.

Obama left immediately after his brief remarks and headed to New York, where he will build support for US action at the UN General Assembly, which has been overtaken by the American assault on Islamic state.

But he did not leave without warning the "overall effort" against IS would take time.

"There will be challenges ahead, but we're going to do what's necessary to take the fight to this terrorist group for the security of the country and the region and for the entire world," Obama said.