United States-led airstrikes late Wednesday targeted oil refineries controlled by Islamic State in Iraq and the Levant (ISIL) in eastern Syria, officials said. The strikes intended to choke off a crucial source of revenue for the group, but they did not halt the fighters' advance in a Kurdish area where fleeing refugees told of villages burnt and captives beheaded.
At least 14 ISIL fighters and five civilians were killed in the attacks, according to the U.K.-based Syrian Observatory for Human Rights.
U.S. officials also said Thursday that attacks on a separate armed organization, the Al-Qaeda-linked Khorasan Group, killed one of its top leaders. The U.S. said it was still assessing whether Mohsin al-Fadhli, a senior Khorasan figure and a former associate of Osama bin Laden, had been killed in the strikes. The Pentagon said any confirmation could take time.
President Barack Obama has pushed diplomats attending the United Nations General Assembly in New York City for help in the fight against ISIL. That effort seems to be paying off, with Belgium announcing it will likely deliver air support and the Netherlands pledging fighter planes.
Saudi Arabia and the United Arab Emirates joined in the strikes earlier this week, with piloted and drone aircraft targeting facilities in northeastern Syria, the U.S. military said on Wednesday.
Turkey, which shares a border with Iraq and Syria, has also relented to Western requests for it to cooperate with the offensive against ISIL, saying it will allow allied forces to launch attacks from its territory.
Ankara had been wary of wading too deep into the fray until last weekend, when ISIL freed 49 captured Turkish citizens. Turkey had feared for their safety if it helped the coalition.
The coalition's call also put Turkey in a tough spot, since Kurdish fighters associated with the PKK, the Kurdish Worker's Party, who have long demanded independence from Turkey, are playing a key role in the fight against ISIL.
Both the U.S. and Turkey consider the PKK to be a terrorist organization, but all three have denounced ISIL.
Kurdish forces have fought the group and, with Turkish help, rescued 150,000 Syrian refugees ISIL has threatened.
U.K. Prime Minister David Cameron told the General Assembly on Wednesday that Britain should join the airstrikes against ISIL in Iraq, adding that his country's parliament has been recalled to secure approval.
"I am therefore recalling the British parliament on Friday to secure approval for the U.K. to take part in international airstrikes against the ISIL in Iraq," Cameron told the 193-member General Assembly.
Although the U.S. airstrikes have been on the table for weeks, Obama wanted to shore up support for the campaign among Arab and Western powers, not because of the firepower added by the allies but to avoid the pitfalls of unilateral intervention that beset the U.S. in the last Iraq invasion.
Obama, speaking at the U.N. on Wednesday, asked the world to join together to fight ISIL and vowed to keep up military pressure against the group.
"The only language understood by killers like this is the language of force, so the United States of America will work with a broad coalition to dismantle this network of death," said Obama.
The U.S. has launched nearly 200 strikes in Iraq in recent weeks against ISIL fighters, who have captured wide areas of land in Iraq and Syria during an offensive that started in June.
The U.S. Central Command said there were 13 strikes late Wednesday against 12 modular oil refineries in Syria controlled by ISIL fighters, as well as another strike that destroyed an ISIL vehicle.
"We are still assessing the outcome of the attack on the refineries, but have initial indications that the strikes were successful," it said on Wednesday.
Modular refineries are prefabricated and constructed off-site so they can be transported and made operational quickly.
Though details of the ISIL’s oil smuggling operations remain vague, the group and its Sunni allies are known to control extensive smuggling routes into Jordan, Turkey and Iran, which some experts believe have been turning a blind eye to the group's illicit tankers and makeshift pipelines.
"These small-scale refineries provided fuel to run [ISIL] operations, money to finance their continued attacks throughout Iraq and Syria, and an economic asset to support their future operations," the U.S. military said.
It is unclear how much crude or refined oil ISIL is managing to sell. But Adam Sieminski, head of the U.S. Energy Information Administration, said on Wednesday that the group is producing less than 100,000 barrels of crude oil a day.
Nicholas Rasmussen, deputy director of the National Counterterrorism Center, testified to U.S. Congress this month that ISIL's war chest probably included about $1 million a day in revenues from black-market oil sales as well as smuggling, robberies and ransom payments for hostages.
Even as airstrikes have hit ISIL outposts, the group's fighters have responded by accelerating their campaign to capture Kobani, a Kurdish city on the border with Turkey. Nearly 140,000 Syrian Kurds have fled into Turkey since last week, the fastest exodus of the entire three-year civil war.
Activists in Syria told Al Jazeera that fighters of Al-Qaeda's Syrian branch, the Jabhat Al-Nusra, were evacuating their bases and positions in the northeastern Syrian province of Idlib. Ahrar Al-Sham, one of the most influential Syrian rebel groups with ties to Al-Nusra, was also evacuating its positions in the region.
The advance on the northern town of Kobani showed the difficulty Washington faces in defeating fighters in Syria, where it lacks strong military allies on the ground.
"Those air strikes are not important. We need soldiers on the ground," said Hamed, a refugee who fled into Turkey from the ISIL advance.
Mazlum Bergaden, a teacher from Kobani who crossed the border on Wednesday with his family, said two of his brothers had been taken captive by ISIL fighters.
"The situation is very bad. After they kill people, they are burning the villages. ... When they capture any village, they behead one person to make everyone else afraid," he said. "They are trying to eradicate our culture, purge our nation."
Al Jazeera and news services