Two senior Russian army officers have been killed in an attack on an armored vehicle in the restive Chechnya region, Russian police reported Sunday. A lieutenant colonel and a major were killed and two other officers were seriously wounded. Police said the armored vehicle was hit by small arms fire and two explosions. Officials said the attack occurred Saturday in the central Shali district. Chechen separatist rebels and Russian forces have fought two wars since the early 1990s. While major fighting in Chechnya ended several years ago, sporadic clashes continue along with rebel bomb attacks on police and soldiers.