The Air Force base in Yemen\'s capital Sanaa was hit by two mortar shells on Sunday evening, but no one was killed or injured, a military official said. \"One of the shells exploded near a small weapon depot causing further explosions and fire, but there were no casualties, while the nearby civil airport (Sanaa International Airport) was undamaged,\" the official told Xinhua on condition of anonymity. Earlier, witnesses said a series of loud explosions were heard near the Yemeni Air Force Base in northern Sanaa.