Fighting in war-torn Yemen’s Marib province between government forces and Iran-backed Houthi militants killed around 50 combatants, including a special forces commander, a government source said Saturday.

Earlier this month, the Houthis resumed a push to capture Marib city, 120 east of the Houhti-held capital Sanaa.

The city lies close to some of Yemen’s richest oil fields and its capture would be major prize for the rebels.

“Twenty-two members of the government forces and more than 28 Houthi militants have died in the last 24 hours in the fighting that continues unabated on the fronts in Marib province,” a government source said.

The Arab coalition launched more than 12 air strikes in support of government forces on the ground, according to the Houthi channel Al Massirah.

On Friday, more than 60 fighters were killed in fighting in Marib, the bloodiest day since the start of the offensive on February 8.

Since then, clashes have resulted in hundreds of deaths among fighters on both sides, according to government sources, and displaced hundreds of families. The Houhtis generally do not disclose their losses.

Yemen has been embroiled in a bloody power struggle since 2014 between its government, supported by Arab coalition, and the Iran-backed Houthi militants, who control most of the north.

The grinding conflict has claimed tens of thousands of lives and displaced millions, according to international organizations, sparking what the UN calls the world’s worst humanitarian crisis.