Syrian activists say suspected U.S.-led airstrikes have killed 14 militants and five civilians in northeastern Syria.
The Britain-based Syrian Observatory for Human Rights said Thursday the overnight strikes hit the Deir el-Zour and Hassakeh areas.
On Wednesday, U.S. forces and those from Saudi Arabia and the United Arab Emirates conducted 13 airstrikes in eastern Syria as part of an operation against the Islamic State group.
U.S. Central Command, which oversees American military operations in the Middle East, said the attacks targeted small-scale oil refineries that generate up to $2 million per day for the militants.
President Barack Obama urged Islamic State fighters to “leave the battlefield while you can” as he addressed the United Nations General Assembly on Wednesday.
Obama blamed sectarian conflicts around the world for creating a “fertile recruiting ground” for groups like the Islamic State, which has taken over parts of Syria and Iraq in a bloody months-long armed campaign.
“There can be no reasoning – no negotiation – with this brand of evil. 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.
Earlier in the opening session, U.N. Secretary General Ban Ki-moon called on world leaders to have a “frank discussion” about the causes of extremism in the region.
“We need a decisive action to stop atrocity crimes,” Ban said, “and frank discussions on what created the threat in the first place.”
In the past week, the Islamic State offensive in northern Syria has displaced more than 130,000 civilians.