BOGOTA, Colombia (AP) – Colombia authorities yesterday were investigating why soldiers killed 10 elite anti-drugs policemen and their civilian informant, an incident the army described as a tragic mistake.

Attorney General Mario Iguaran, who travelled yesterday to the site of the killings, Jamundi, 300 kilometres (195 miles) southwest of Bogota, called Monday’s incident “serious and regrettable.”

Acting on a tip from the informant about a large stash of drugs, the members of an elite unit of the judicial police, known as the DIJIN, were traveling to a safe house when they stumbled across a military patrol.

In the ensuing clash all the police, who apparently did not have time to react, and the informant were killed.

The military said the incident was a case of mistaken identity, due partly to soldiers being on edge for rebel attacks aimed at sabotaging Sunday’s presidential elections. A spokesman for the army would not say if any action had been taken against the soldiers, only that they were being investigated.

In addition to Iguaran, a commission made up of generals from Colombia’s security forces will investigate the case.

“I call on this commission to work quickly and tell the country what really happened,” President Alvaro Uribe said late Monday.

Authorities said investigators would have to determine why the attack on the policeman was so deadly that none survived and why the police didn’t have time to react to the attack.

The police, while not in uniform, were clearly identifiable by their caps and jackets, said the head of the DIJIN, General Oscar Naranjo. In addition, the attack occurred in daylight at around 6 pm.

“We are looking at the loss of an elite unit, recognised nationally and internationally for its work in capturing dozens of drug-traffickers for extradition, hundreds of seizures of drugs,” Naranjo told Caracol radio.