The US-baked Syrian Democratic Forces (SDF) launched a new offensive on Saturday to oust ISIS from swathes of Syria’s eastern Deir Ezzor province, a top commander announced.

The SDF, which is backed by US-led air cover and special forces on the ground, is already fighting for ISIS’ de facto capital in Raqqa, and its fighters will now aim to clear the militants from territory east of the Euphrates River, close to the Iraqi border, said Ahmad Abu Khawlah in a statement.

A senior SDF official told Reuters on Friday they would launch attacks from the south of Hasaka, which is controlled by the Kurdish YPG militia, as part of a wider offensive to drive ISIS out of Raqqa city and territory to its southeast.

Spearheaded by the YPG, the SDF says it has taken 65 percent of Raqqa city from ISIS.

Syrian regime forces are fighting a separate offensive to oust the terrorist organization from the Deir Ezzor provincial capital.

The Syrian forces and their Iran-backed allies recaptured the Teym oilfield from ISIS near the city on Saturday in further advances against the militants, state TV reported.

Regime forces also seized part of a main highway running from Deir Ezzor down to the city of al-Mayadeen, to which many ISIS militants have retreated, the Syrian Observatory for Human Rights monitoring group said.

The British-based group said that advance would block potential ISIS reinforcements from al-Mayadeen.

The dueling battles for Deir Ezzor highlight the importance of the oil-rich province.

The race to reach the Iraqi border will also shape future regional dynamics, determining whether the US or Russia and Iran will have more influence in the strategic area once the extremist group is defeated.