The head of the army has accused his troops, including two officers, of participating in a deadly car-bombing on the eve of President Alvaro Uribe's swearing-in ceremony last month that was originally blamed on left-wing rebels.
The revelations come with the army already reeling from a series of scandals linking troops to drug traffickers and extra-judicial killings of civilians.
General Mario Montoya, head of the army, said in a brief statement deploring the alleged actions of his subordinates that initial accusations against left-wing rebels "didn't correspond to the reality". He said the army was co-operating fully with prosecutors investigating the two unnamed officers and other soldiers.
On 31 July, a week before President Uribe was sworn in, a car bomb exploded in Bogota as trucks carrying soldiers passed by. One civillian was killed and 10 soldiers hurt.
The blast came as a shock to Bogota's residents, who have grown accustomed in recent years to living out of harm's way and seeing political violence related to their country's four-decade-old civil war on the evening news, not their own streets.
Bogota's main daily newspaper, El Tiempo, said on its website on Thursday that authorities had video and taped phone conversations, in addition to witness testimony, linking four army officers - including a colonel - with the attack. The newspaper said the officers remain on active duty even though the accusations had been known about for more than three weeks.
General Montoya also said corrupt soldiers were behind the high-profile seizures in recent weeks of several weapons stockpiles. The authorities originally said the weapons belonged to rebels but the seizures now appear to have been staged by soldiers to impress their superiors.
Colombia's army - the main recipient of more than $4bn (£2.1bn) in US anti-narcotics military aid since 2000 - is struggling to clear its battered reputation, with officers accused of trying to pass off as rebels the bodies of innocent civilians killed illegally.
An army colonel and his platoon have also been arrested for the ambush of an elite anti-narcotics unit near the southern town of Cali. General Montoya originally said it was a case of friendly fire, but prosecutors believe that the attack was performed on behalf of drug traffickers.
General Montoya was the only one of Colombia's top four military chiefs to hold on to his job after a shake-up of the armed forces that coincided with the start of Mr Uribe's second four-year term.Reuse content