With the death of three senior Colombian rebel commanders, the bloodless rescue of 14 top hostages, and the seizure of thousands of guerrilla computer files, this should have been a triumphant year for Colombia's military.

The Army's successes, however, have been muted by a macabre revelation that the Colombian military reportedly killed civilians to inflate their rebel body count in an effort to appear more successful.

Although nongovernment organizations (NGOs) have tracked the practice for years, many in Colombia are just now waking up to news about the systematic killings. As Colombian government officials act to purge military officers implicated in the killings and create a monitoring program, the padded body counts have put the military's methods under close scrutiny.

This week, Colombian officials began holding military officials accountable for the slayings. After Colombian President Álvaro Uribe summarily fired 20 top officers, including three generals and 11 colonels, Gen. Mario Montoya, head of the Army, resigned on Tuesday. The terminations follow an internal probe into the disappearance of at least 11 civilians from a Bogotá suburb, whose bodies were later found halfway across the country and reported as combat casualties.

But this incident is only one of hundreds of similar cases reported over the past six years, in what Navi Pillay, the United Nations High Commissioner for Human Rights, said appeared to be a "systemic and widespread" phenomenon.

It's unlikely that the practice of killing civilians became widespread as a result of military orders, says César Restrepo, a military analyst with the Security and Democracy Foundation, a think tank in Bogotá.

He points to a lack of command and control in the military and misguided incentive policies that rewarded soldiers with extra leave for every killed or captured rebel.

"The government put blind faith in the military to corner the FARC [Revolutionary Armed Forces of Colombia] but didn't bother to put controls in place," says Mr. Restrepo.

Additionally, many commanders, under pressure to produce results, dismissed reports of the "false positives," the Colombian expression for civilians listed as combat casualties, as rebel generated lies. Although the Defense Ministry issued a directive last year saying success in this country's 40-year conflict with leftist rebels would no longer be measured in body bags, incentives remained in place. As of Oct. 31, Colombian troops had reported 1,584 members of illegal groups killed in combat.

This may soon change though, as Mr. Uribe announced on Thursday that every military unit down to the battalion level will have an appointed official who receives and processes allegations of abuse. He has asked the UN to help monitor this program.

The Colombian inspector general's office is investigating more than 930 extrajudicial executions since 2002, while a federation of human rights groups, known as the Colombia-Europe-United States Coordinator tallied at least 535 between January 2007 and July 2008.

"The sad part is that even if they had been real guerrillas, those deaths have no impact on the conflict," says Restrepo. "What's needed is a change of mentality, and that takes years."

Colombia receives an average of $500 million per year in aid from the United States, predominately for military use. Units that receive US funding must have a clean human rights record. Three of the units commanded by officers fired last week lost their eligibility to receive US money. The units had been previously cleared as free of human rights violations.

The Army's new commander, Gen. Óscar González, who officially assumed the post on Thursday, commanded two of the most heavily questioned units in relation to extrajudicial killings.

In its latest report on Colombia issued last week, Amnesty International urged a suspension of military aid until Colombia follows UN recommendations for ending the conflict, "so there is no longer a clear risk of such assistance and equipment being used to facilitate serious violations of human rights," the report said.