BEIRUT (AP) — A U.S.-backed Syrian fighting force says it has launched a campaign to clear the Islamic State group from its last pocket in northeast Syria.

The Syrian Democratic Forces says operations began on Monday to expel IS militants from the town of Hajin and surrounding villages on the northeast banks of the Euphrates River.

The SDF is supported by the U.S.-led international coalition against IS.

The Syrian Observatory for Human Rights monitoring group says coalition jets have bombed locations across the IS pocket in conjunction with the SDF ground offensive. The group says at least 23 IS fighters have been killed in the first 24 hours of battle.

The jihadist group today holds just a fraction of the territory it held at its 2014 peak.