At least 34 Yemeni Houthi rebels were killed by Saudi-led coalition airstrikes in Yemen’s central province of Marib on Sunday, a Houthi security source told Xinhua.

“The airstrikes targeted the Houthi fighters in Sirwah district while they were on the back of three pick-up military vehicles on their way to a frontline in the district,” the Houthi security source in Sirwah said on condition of anonymity.

Houthi-run al-Masirah TV also reported the coalition airstrikes in Sirwah district in eastern Marib, without providing more details.

The gas-producer province of Marib, about 173 km east of the capital Sanaa, is under control of the Yemeni government, while the Houthi rebels have been trying to advance to some eastern and southern districts.

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

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