The U.S.-led coalition conducted 10 air strikes against ISIS in Syria Sunday and 17 in Iraq, the U.S. military said, stepping up its air assault in Syria as fighting on the ground escalated. In Syria, six air strikes near Mar'a destroyed three fighting positions, an ammunition cache and three ISIS buildings, the Combined Joint Task Force said in a statement Monday. Two air strikes destroyed a vehicle and wounded three ISIS fighters near the militant stronghold of Raqqa, while one strike each targeted militants near al Hawl and al Hasakah, it said. Fighting escalated in Syria over the weekend after talks in Vienna Friday called for a ceasefire. ISIS fighters drove Syrian government forces from a western town of Maheen in Homs province. The coalition campaign upped the number of air strikes in Syria over the weekend, with 26 strikes since Friday, compared with only two the previous week. In Iraq, the coalition continued to target the contested cities of Ramadi and Sinjar with four and five strikes respectively, denying militants access to terrain around Ramadi, the military said. Other strikes hit near Mosul, Tal Afar, Baiji, Kisik, Makhmur and Habbaniyah, it said.