Turkey-backed Syrian rebels have seized control of almost all of Syria’s al-Bab and are now working to find and clear mines.

Turkey-backed Syrian rebels have seized control of almost all of Syria’s al-Bab and are now working to find and clear mines, Turkey’s defense minister told state-run Anadolu news agency on Thursday.

The Free Syrian Army, backed by Turkish tanks, warplanes and special forces, have entered the center of al-Bab, a town they have been besieging for weeks, Isik said in an interview with Anadolu.

Turkey launched its Syrian operation, dubbed “Operation Euphrates Shield,” in August, an effort to push ISIS from its border and stop the advance of a Syrian Kurdish militia.

Taking control of al-Bab, an ISIS stronghold 30 km (20 miles) from the Turkish border, would deepen Turkish influence in an area of Syria where it has effectively created a buffer zone and would allow the Ankara-backed forces to press on towards Raqqa, ISIS’s de facto capital in Syria.

The Free Syrian Army fighters, a loose coalition of Syrian Arabs and Turkmen, have been attacking al-Bab since December, aided by Turkish warplanes, tanks and special forces.

Turkey’s state-run Anadolu Agency, citing its correspondent in al-Bab, said the rebels had seized control of the town center and were now clearing mines and explosive devices laid by the extremists. Some 1,900 square kilometers (734 square miles) in northern Syria has now been cleared of militant groups, it said.

“We had reached the city center yesterday but there was a suicide attack so we had to withdraw a little bit. And today we attacked again. I can say that 85-90 percent of the city is under control,” a fighter from the Sultan Murad Brigade who is in al-Bab told Reuters by telephone.

“They have dug tunnels all under Bab and those who have remained are all suicide bombers. The whole of the city is mined. I can say that every meter is mined.”

There was no immediate comment from the Turkish military.