Internal armed conflict has resulted in the killing of many people in a number of countries. Killings may be carried out by government as well as opposition forces, and there are frequent reports of the indiscriminate killing of non-combatant civilians by government forces in areas where guerrillas are active. Intensive counter-guerrilla operations may use the strategy of emptying areas of the entire civilian population in order to eliminate any possible support for the guerrillas, and often indiscriminate killings occur, involving entire village populations including women and children. Villagers are also abducted and killed by 'death squads' under military control; torture and mutilation are routinely practised. In some cases, people trying to flee the areas of armed conflict or those who reached refugee camps in neighbouring countries are indiscriminately attacked by government forces; many are killed. Often it is claimed that those villages and refugee camps were infiltrated by guerrilla forces and that death occurred in armed clashes between government troops and guerrilla forces. In a number of countries a state of siege or a state of emergency is imposed and constitutional guarantees for human rights are suspended or severely curtailed. In some countries heavy security measures are enforced and arbitrary arrest and detention of those suspected of their involvement with guerrilla movements frequently result in the execution of detainees.