AIN ISSA, Syria: The U.S.-led coalition will have “a great deal more” to do in Syria even after defeating Daesh (ISIS) in its northern Raqqa bastion, a deputy commander of the coalition said Sunday.

“Daesh is not defeated with the liberation of Raqqa. The defeat of Daesh was not completed with the liberation of Mosul” in Iraq, British Maj. Gen. Rupert Jones told reporters. Speaking in the town of Ain Issa 50 kilometers north of Raqqa, Jones said: “We know as an international coalition there’s still a great deal more to do here in Syria.”

He said that the U.S.-backed Arab-Kurdish alliance known as the Syrian Democratic Forces “have proved themselves to be a reliable counter-Daesh partner.” “We will continue to work with the Syrian Democratic Forces to complete the defeat of Daesh,” Jones said.

The U.S.-backed forces have successfully routed Daesh from several areas in Syria since their creation in 2014. They have spent months encircling Raqqa, the de facto capital of Daesh’s Syrian territory since 2014, and finally broke into it in early June, seizing several neighborhoods.

But for the past week they have encountered fierce resistance from the militants, and progress has also been hampered by the presence of civilians trapped in Raqqa city center.

“It is every bit as tough as we expected but there’s no surprise in that so there are not currently any plans for us to divert more, to require more forces,” Jones added.

He also said the “protection of civilians” was of key concern to the coalition. U.S. Army Col. Ryan Dillon estimates there are around 2,000 Daesh militants in the northern city.

Dillon added that the militants are using many of the same tactics employed in the Iraqi city of Mosul, including the use of tunnel networks, vehicle-borne IEDs and drones.

But he said in Raqqa, more than in Mosul, the militant group relies more on using civilians, sometimes children, to prevent coalition forces from striking specific areas in the city.

According to the coalition, 603 civilians have been killed in U.S.-led strikes on Iraq and Syria since the air campaign against the militants was launched towards the end of 2014.

But Airwars, a London-based collective of journalists and researchers that tracks civilian deaths in Iraq and Syria, says 744 civilians were killed in coalition strikes in Syria and Iraq in the month of June alone.