The U.S. and Arab allies unleashed a new round of airstrikes against Islamic State militants in eastern Syria late Wednesday, targeting a dozen small oil refineries.
U.S. officials told Fox News the latest round of strikes was designed to target a dozen so-called “modular oil refineries”-- essentially small, ISIS-built refineries that the terror group uses to fuel its vehicles and to fund its operations. “This is not going to look like the oil fields burning in Iraq,” one official said, referring to the Gulf War.
A Department of Defense official said ISIS made roughly a $2 million a day profit from the modular oil refineries, which produced 300 to 500 barrels a day.
Officials said all the aircraft made it back safely from the strikes.
The U.S. Central Command said in a statement partner nations in the mission included Saudi Arabia and the United Arab Emirates and the 13 airstrikes were conducted by both piloted aircraft and drones. Initial indications were the strikes were successful, the statement said.
U.S. officials said the goal was to leave the refineries largely intact, so they eventually could be used again, but to destroy the support facilities used by ISIS.
Earlier airstrikes Tuesday and Wednesday in Iraq and Syria were carried out by a mix of attack, bomber and fighter aircraft.
Two airstrikes west of Baghdad destroyed two ISIS armed vehicles and a weapons cache. Another two airstrikes, southeast of Irbil, destroyed ISIS fighting positions.
A fifth airstrike damaged eight ISIS vehicles in Syria in an area northwest of the Iraqi town of Al Qa'im, according to U.S Central Command.
All aircraft exited the area safely.
A senior defense official told Fox News that Jordan also conducted an airstrike against ISIS in Syria on Wednesday.
In a separate statement, Pentagon spokesman Rear Adm. John Kirby said the strikes in eastern Syria hit a staging area used by the militants to move equipment across the border into Iraq.
He did not specify exactly where the air raids took place, but the Iraqi town of Al Qa'im is across the border from the Syrian town of Boukamal, where Syrian activists reported at least 13 airstrikes on suspected Islamic State positions on Wednesday.
The Britain-based Syrian Observatory for Human Rights said it was not immediately clear who carried out the airstrikes in and around Boukamal, but it cited locals as saying the intensity of the air raids was similar to that of strikes on the town early Tuesday by the U.S.-led military coalition.
To date, the U.S. Central Command says it has conducted 198 airstrikes against ISIS in Iraq and 20 in Syria – with the help of partner nations.
In the opening salvo of the campaign, the U.S. on its own also hit Al Qaeda's Syria branch, known as the Nusra Front. American officials said the strikes targeted the so-called Khorasan Group, which the U.S. says consists of hardened jihadis who pose a direct and imminent threat to the United States.
On Wednesday, the Nusra Front said it was evacuating its compounds near civilian areas in Idlib province in northwestern Syria. The announcement, made on a Facebook page associated with the group's Idlib operations, follows a U.S. airstrike on a Nusra Front base in the village of Kfar Derian that killed around a dozen fighters and 10 civilians, according to two activists.
Another Syrian rebel group, Ahrar al-Sham, was also clearing out of its bases, weapons workshops and offices, according to the Observatory. It said the group issued a statement calling for fighters to limit the use of wireless communication devices to emergencies, to move heavy weapons and conceal them, and to warn civilians to stay away from the group's camps.
An activist in Idlib who goes by the name of Mohammed confirmed that Ahrar al-Sham was evacuating its bases throughout the northern area. He said he was not aware of any strikes against the group, but said the fighters thought they would be targeted by the coalition because of their ultraconservative Islamic beliefs.
Ahrar al-Sham has been among the steadiest and most effective forces fighting to oust President Bashar Assad in Syria's civil war. It has also been on the front lines of a nine-month battle in northern Syria against the Islamic State group. But the U.S. has long looked at Ahrar al-Sham with suspicion, considering the group too radical and too cozy with the Nusra Front.
The U.S.-led campaign in Syria has drawn a mixed response from the country's multitude of rebel brigades, many of whom cooperate with the Nusra Front and have been locked in a deadly fight with Islamic State militants since January. But the rebels' ultimate goal is to topple Assad, while the U.S. is focused on defeating the Islamic State group.
On Wednesday, the main Western-backed Syrian opposition group criticized the American-led airstrikes for being limited to the Islamic State group and other extremists while leaving Assad's government untouched.
"We regret that the international community has come up with partial solutions to the Syrian conflict in which hundreds of thousands were killed or detained by the Assad regime," said Nasr al-Hariri, secretary general of the Syrian National Coalition.
In a statement, al-Hariri also said that any effort other than helping Syrians overthrow Assad will only fuel extremism.
Fox News' Justin Fishel and The Associated Press contributed to this report.