The Saudi-led coalition launched 15 airstrikes on Yemen’s Houthi militia in and around the oil-rich province of Marib on Saturday, the Houthi-run al-Masirah TV reported.

Eleven airstrikes hit targets in the western Sirwah district, two in the northwestern Madghal district, and two in the southwestern Natie district, according to the Houthi television, without providing further details.

Meanwhile, a Yemeni government military source told Xinhua that the government army, with the assistance of the Saudi-led coalition warplanes, repelled attacks by the Houthi militia on several frontlines in the three districts on Saturday.

Dozens of the Houthi fighters were killed in the battles, while several government soldiers were wounded, the source said on condition of anonymity.

The Iran-backed Houthis began a major offensive against the Saudi-backed Yemeni government army to capture Marib in central Yemen, which hosts over 2 million internally displaced people.

The United Nations said agencies have warned that the assault on Marib could lead to a major humanitarian catastrophe.

On Wednesday, UN Special Envoy for Yemen Martin Griffiths said a recent UN-brokered negotiation between Yemen’s warring sides and other relevant parties has failed to produce any agreement of cease-fire.

Yemen has been mired in a civil war since late 2014 when the Houthi militia seized control of several northern provinces and forced the internationally recognized government of President Abd-Rabbu Mansour Hadi out of the capital Sanaa.

The Saudi-led Arab coalition intervened in the Yemeni conflict in March 2015 to support Hadi’s government.