Sanaa, Nov 25 : Two persons were killed and two injured when Saudi-led coalition airstrikes hit a building under construction in Yemen's Houthi-held capital Sanaa, Houthi-run al-Masirah TV reported. The airstrikes on Wednesday also destroyed a factory for producing plastic materials, the Houthi television reported without providing further details. Both sites under attack are located in northern Sanaa, Xinhua news agency reported. Meanwhile, the coalition announced that its operation targeted secret sites used by the Houthi militia for storing and firing "bomb-laden drones, including a building under construction used as a secret factory for assembling the drones," the Saudi-owned Al-Arabiya TV reported. The Iran-backed Houthi militia has recently intensified cross-border missile and drone attacks against Saudi cities. In February, the Yemeni rebel group began a major offensive against the Saudi-backed Yemeni government army to capture the oil-rich province of Marib in central Yemen. /IANS