Sanaa, Dec 27 : At least 18 Yemeni soldiers were killed in fighting between the army and Houthi militia in the oil-rich province of Marib, a government military source. "Eighteen soldiers were killed today in the battle in the desert area of al-Balak al-Sharki in southern Marib," the source told Xinhua news agency late Sunday. "There were also many Houthis killed in the battle by airstrikes carried out by the Saudi-led Arab coalition," he said, without providing a specific number. The Houthi-run al-Masirah TV reported 16 coalition airstrikes on al-Balak al-Sharki area without providing further details. The Iran-backed militia have made major advances in the past months in Marib, seizing control of several districts around the government-controlled central city. In February, the rebel group began a major offensive to capture the oil-rich province, the last northern stronghold of the Saudi-backed Yemeni government. /IANS