Sanaa, Aug 14 : The Yemeni army killed 21 Houthi rebels when repelling attacks in the central province of Marib in the last 24 hours, a military source said. In Al-Kasarah frontline northeast of western Sirwah district, "the army repelled Houthi rebel attacks from two directions on Malbodah heights that were recaptured by the army two days ago, killing 14 rebels and recapturing the highway linking Al-Kasarah with the northwestern district of Raghwan", the source in Marib told Xinhua news agency on Friday. "The army also advanced onto the west of Al-Kasarah area, attempting to recapture Al-Makhdarah heights, west of Hilan mountain that overlooks the nearby southern frontline of Al-Mashjah." In the southwestern district of Rahabah, "the army repelled rebel attacks on the strategic mountain of Al-Abzakh that the army recaptured earlier this month, killing at least seven", the source said. Meanwhile, the Houthi-run al-Masirah TV made no report on the ground fighting, but said the Saudi-led coalition warplanes launched 12 airstrikes on the Houthi positions in Sirwah and Rahabah. The Saudi-owned Al-Arabiya TV reported that the coalition intercepted and destroyed a bomb-laden drone launched by the Iran-backed Houthi militia towards the Saudi city of Khamis Mushait. Yemen's civil war flared up in 2014 when the Houthi group seized control of much of the country's north and forced the internationally recognised 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. The Houthi group has stepped up cross-border drone and missile attacks on Saudi Arabia since February when they launched a major offensive on Marib in attempts to seize control of the oil-rich province. The US has warned that the offensive on Marib, which hosts nearly 1 million internally displaced people, could lead to a major humanitarian catastrophe. /IANS