The United States and its Arab allies bombed Syria for the first time on Tuesday, killing dozens of Islamic State (IS) fighters and over 50 members of the Nusra Front.
The US department of defence said on its official Facebook page on Tuesday that military forces of the US and its Arab allies, including Bahrain, Jordan, Saudi Arabia, Qatar and the United Arab Emirates, undertook military action against IS terrorists in Syria overnight.
The White House also reported that President Barack Obama is to make a statement within hours on the strategy against Islamic State following the airstrikes.
According to the defence department, 14 strikes were conducted against IS using a mix of fighter bombers, remotely piloted aircraft and Tomahawk Land Attack Missiles.
The strikes destroyed or damaged multiple IS targets in Raqqa, Dayr Az-Zawr, Al-Hasakah, and Abu Kamal.
According to the Syrian Observatory for Human Rights, US airstrikes killed 50 Al-Qaeda militants and eight civilians, including children, in northern Syria.
Separately, US forces acting alone launched strikes in another area of Syria against an Al-Qaeda-linked group, Nusra Front, to "disrupt [an] imminent attack" against US and Western interests by "seasoned Al-Qaeda veterans," Central Command said.
Strikes targeting Nusra Front in the northern provinces of Aleppo and Idlib killed at least 50 fighters and eight civilians. The Nusra Front is Al-Qaeda's official Syrian wing and Islamic State's rival. The Observatory said most of the fighters killed there were not Syrians, Reuters reported.
The air attacks fulfil Obama's pledge to strike against IS in Syria.
The Islamic State later vowed revenge and blamed Saudi Arabia for allowing the strikes to take place.
The strikes took place hours before Obama goes to the UN General Assembly in New York where he will try to rally more nations behind his drive to destroy Islamic State.
US forces have previously hit Islamic State targets in Iraq, where Washington supports the government, but had held back from a military engagement in Syria, where the United States opposes President Bashar Al-Assad.
The Syrian government said it was informed by Washington hours before the strikes.
Secretary of State John Kerry had sent a letter to Damascus through his Iraqi counterpart.
Syria said Tuesday that it supported "any international effort" to combat jihadists, hours after a US-led coalition launched strikes against the Islamic State group in the war-torn country.
Syria "backs any international effort that contributes to the fight against terrorists, be it against... IS, (Al-Qaeda affiliate) Nusra Front or anyone else," the foreign ministry said in a televised statement.
The United States has previously said it would not coordinate with Assad's government.
Washington says Assad must leave power, particularly after he was accused of using chemical weapons against his own people last year.
The Western-backed Syrian opposition, which is fighting against both Assad and Islamic State, welcomed the air strikes which it said would help defeat Assad.
As Reuters reported, the targets included Raqqa city, the main headquarters in Syria of Islamic State fighters who have proclaimed a caliphate stretching from Syria's Aleppo province through the Tigris and Euphrates river valleys to the outskirts of Baghdad.
Photographs taken in Raqqa showed wreckage of what an Islamic State fighter said was a drone that had been shot down. Pieces of the wreckage, including what appeared to be part of a propeller, were shown loaded into the back of a van.
A video posted online, filmed through night-vision apparatus, showed lights from jets flying overhead firing a stream of projectiles at the ground. It was not clear where or when the video was filmed.
Jordan, confirming its participation, said its air force had bombed "a number of targets that belong to some terrorist groups that sought to commit terrorist acts inside Jordan," although it did not specify any location.
Israel shot down a Syrian aircraft over air space it controls in the Golan Heights but there was no indication the incident, confirmed by Syria, was linked to the US action.