US-allied forces said today that they have captured Syria's largest oil field from the Islamic State(IS) group. The Kurdish-led Syrian Democratic Forces (SDF), who are in a race with Russian-backed Syrian troops to seize parts of the oil-rch Deir el-Zour province, said they are in full control of the Al-Omar field. The SDF has already driven IS from Deir el-Zour's main natural gas field and smaller oil fields. It says government forces are three kilometers away from the fields. The Syrian Observatory for Human Rights says, pro-government forces retreated from the area around Al-Omar field after coming under heavy fire from IS militants. <br/>IS has suffered a series of major setbacks in recent months, including the loss of the Syrian city of Raqqa and the Iraqi city of Mosul.