BEIRUT (AP) — Syrian opposition activists and state media say government forces are close to breaking a nearly three-year siege imposed by the Islamic State group on parts of the eastern city of Deir el-Zour.

Syrian troops and allied militiamen have for months been advancing toward Deir el-Zour, the provincial capital of the oil-rich province of the same name. Government forces are besieged in a handful of neighborhoods as well as a nearby airport.

The Britain-based Syrian Observatory for Human Rights said Monday that the advancing forces are less than 10 kilometers (6 miles) from a besieged, government-held air base known as Brigade 137. If they reach the base, they will be able to lift the siege.

State news agency SANA is reporting the "collapse" of IS defenses in the area.