The International Committee of the Red Cross has voiced grave concern over what it says is Colombia's apparent "deliberate misuse" of its symbol.
The ICRC said it had seen video footage that suggested the emblem was used deliberately in July's military mission to free 15 hostages from rebel hands.
The government has apologised to the ICRC but also condemned the leak of the military video to Colombian TV.
Intentional misuse of the symbol would be a breach of the Geneva Conventions.
The Geneva-based ICRC says the footage shown on Colombian TV on Monday indicates that the emblem was being used before the operation to free the hostages from Farc guerrillas had even begun, indicating intentional misuse.
"If authenticated, these images would clearly establish an improper use of the Red Cross emblem, which we deplore," said ICRC deputy director of operations Dominik Stillhart.
Mr Stillhart said they were seeking further clarification from the Colombian government.
Rescuers tricked rebels into releasing French-Colombian politician Ingrid Betancourt and the other hostages by posing as international aid workers.
Colombian President Alvaro Uribe subsequently acknowledged that a Red Cross symbol was worn by a member of the military taking part in the 2 July rescue mission.
Colombian Defence Minsier Juan Manuel Santos (left) and armed forces chief Gen Freddy padilla (right) on 5 August
The leak of the video could amount to treason, the defence minister says
Mr Uribe said he had apologised to the Red Cross for the error, which he said had been made by a nervous soldier acting against orders.
Speaking on Tuesday, after the video was shown on Colombian TV, Defence Minister Juan Manuel Santos apologised again to the ICRC.
"The emblem...was used from the beginning of the operation. We are very sorry that this has happened. But the government, the president and (armed forces chief) General Padilla said the truth that we knew at the time," Mr Santos said.
But Mr Santos also condemned the leak of the video, saying those responsible had been identified and would be punished.
"This video contains material that was leaked by members of the security forces, from our army. This leak was a product of disloyalty, possibly corruption or even treason because it puts at risk the lives of people who are dedicated to defending the fatherland," he said.
The Colombian government has said the rescue was the result of long preparation, eavesdropping on rebel communications and deception of guerrillas on the ground, allowing the hostages to be liberated without loss of life.
Officials also stressed how the mission had been carried out without loss of life.
Falsely portraying military personnel as Red Cross workers is against the Geneva Conventions because it could put humanitarian workers at risk when carrying out missions in war zones.
It also undermines the neutrality of the Red Cross.
At the end of July, Farc guerrillas handed eight people they had kidnapped the week before to ICRC representatives, suggesting the rebels have not lost faith in the humanitarian organisation, correspondents say.
The Revolutionary Armed Forces of Colombia (Farc) have been fighting the Colombian state for more than four decades and are believed to still hold several hundred hostages