US and Arab warplanes hammered militants of the so-called ’Islamic State of Iraq and the Levant’ (ISIL) in eastern Syria early Tuesday, opening a new front in the fight against the terrorist group.

US and Arab warplanes hammered terrorist militants of the so-called 'Islamic State of Iraq and the Levant' (ISIL) in eastern Syria early Tuesday, opening a new front in the fight against the terrorist group, U.S. defense officials said.

Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates took part in the bombing raids, US media reported.

"I can confirm that US military and partner nation forces are undertaking military action against ISIL (Islamic State group) terrorists in Syria using a mix of fighter, bomber and Tomahawk Land Attack Missiles," Pentagon spokesman Rear Admiral John Kirby said in a statement.

Later in the day, Jordan confirmed that it joined the US-led strikes.

"We took part in the strikes which are part of our efforts to defeat terrorism in its strongholds," government spokesman Mohammad Al-Momani said.

The decision to conduct the air strikes was undertaken on Monday by the head of US Central Command, General Lloyd Austin, "under authorization granted to him by the commander in chief," Kirby said.

"We will provide more details later as operationally appropriate."

The UK-based opposition Human Rights Observatory said that coalition air strikes killed 30 Al-Qaeda militants in western Aleppo province.

The toll came after the Pentagon confirmed eight strikes against "seasoned Al-Qaeda veterans" in the province, saying the raids disrupting "imminent attack plotting against the United States and Western interests".

The strikes focused on ISIL positions in Raqa, a stronghold for the extremists, as well as targets along the Iraq-Syria border, according to a second Pentagon official, who spoke on condition of anonymity.

US F-22 fighter jets, America's most sophisticated warplane, were scheduled to take part in the raids as well -- the first combat mission for the costly aircraft, the second official said.

Along with "ongoing" air raids, the US military fired Tomahawk cruise missiles from warships in the Gulf and Red Sea, the official said.

The US-led coalition hit ISIL targets in the eastern province of Deir Ezzor early as well, the Observatory said.

Most of the targets hit were in the Deir Ezzor town of Albu Kamal on the Iraq border, the Observatory stated.

"The coalition carried out 22 air and missile strikes against the town of Albu Kamal," it noted.

The wave of strikes came less than two weeks after Obama warned that he had approved an expansion of the campaign against the terrorist group to include action in Syria.

The air strikes in Syria came as Kurdish militia fought to defend a key border town in northern Syria, after 130,000 terrified residents fled to Turkey to escape an ISIL terrorist advance.