Sanaa, Feb 21 : Nine Yemeni soldiers were killed in a landmine explosion in the country's northern province of Saada, a stronghold of the Houthi militia, a military official said. "A military patrol of the pro-government forces was struck by an anti-vehicle landmine laid previously by the Houthi rebel militia in Albuqa in Saada," the official told Xinhua news agency. The landmine explosion destroyed the military vehicle and left at least nine soldiers dead at the scene, he said. The Houthi militia has recently laid hundreds of landmines and various types of improvised explosive devices (IEDs) near Saada, he said. The Houthis surrounded their main stronghold with large fields of landmines in an attempt to block the Saudi-backed Yemeni government forces from advancing toward their bastions, according to the official. Previous reports by several humanitarian organisations indicated that Yemen has become one of the largest landmine battlefields in the world since World War II. Yemen has been mired in a civil war since late 2014 when the Iran-backed Houthi militia seized control of several northern Yemeni 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. /IANS