Colombia report reveals deadly extent of five-decade conflict BOGOTA (Reuters) - Almost a quarter of a million Colombians have been killed over the last 54 years of bloody strife, most of them civilians, a government-funded report revealed on Wednesday, providing fresh evidence of the vast scale of human rights violations since hostilities began. The study examined atrocities that have occurred since 1958, when radicals began to form the nation's two biggest insurgent groups and right-wing paramilitaries took up arms three decades later, said Gonzalo Sanchez, head of the investigation, which took six years to complete. Colombia has been fighting a war with two leftist rebel groups since they were officially founded in 1964, after a long period of civil war known as La Violencia. The FARC, or Revolutionary Armed Forces of Colombia, and ELN, or National Liberation Army, also battled paramilitary groups, leaving civilians caught in the middle. We all deserve to know the truth, we all deserve to understand what happened in our rural areas and cities, and only then will we be able to say with force: Stop! Colombian President Juan Manuel Santos said at the presidential palace on Wednesday, when the study was released. Only in a Colombia without fear and with truth can we begin to turn the page. The government has been engaged in peace talks with the FARC since November. While human rights violations have receded, the report painted a grim picture of bloodshed from the height of the conflict until 2012. Colombia's armed forces, backed by billions in U.S. aid, have used better intelligence and logistics over the last decade to combat the illegal armed groups, pushing their fighters deep into inhospitable jungle terrain. It's a war that has left most of the country mourning, but very unevenly. It's a war whose victims are, in the vast majority, non-combatant civilians. It's a depraved war that has broken all humanitarian rules," said Sanchez, who presented the report to Santos. In more than a half century, the war killed 220,000 Colombians, more than 177,300, or 80 percent, of whom were civilians, according to the report. Another 40,787 members of the armed forces, paramilitary and rebels groups were killed in combat. The 400-page study, packed with shocking photos of victims, was conducted in some of Colombia's most volatile areas, where communities have lived in fear for decades. It details the types of violence used by each group. The bloodiest period was between 1985 and 2002, when the paramilitaries formed to defend landowners and business leaders against rebel attacks. The paramilitaries, known as the United Self-Defense Forces of Colombia, or AUC, were responsible for some of the most atrocious human rights violations. Paramilitary groups, guerrillas and members of the armed forces committed 1,982 massacres - defined as four victims or more - killing 11,751 between 1980 and 2012. The AUC was responsible for the bulk of the massacres, while guerrillas kidnapped more and were responsible for most attacks against infrastructure. The study found 4.7 million had been displaced since 1996, 27,023 victims were kidnapped since 1970, and 1,190 indigenous Indians were killed between 1996 and 2009. Reporting by Helen Murphy; Editing by Stacey Joyce