Suspected bogus police stole an estimated US$15-million in cash in a daring late night robbery at Johannesburg's O.R. Tambo International Airport.

The heist occurred when "police" stopped GuardForce personnel as they were transporting the money to an awaiting flight bound for London on Tuesday night.

Airports Company South Africa’s O.R. Tambo International Airport said in a short statement the robbery occurred at approximately 7.45pm.

"No shots were fired and no injuries have been reported. The robbers fled‚" it said in a statement.

"South African Police Service (SAPS) and Airports Company South Africa is working closely with other security agencies to apprehend the suspects.

"The investigation is at an early stage. Updates will be provided when more information is available."

The airport authority said "it is not known at this stage what‚ if anything‚ was taken during the incident" but independent sources told TimesLIVE that an estimated US$15-million in cash was stolen.

GuardForce is responsible for securing high risk cargo‚ such as money‚ precious metals and diamonds‚ at a cargo storage facility at the airport.

Separate and independent sources told TimesLIVE from the scene that the attack occurred as the GuardForce employees approached the aircraft.

"A van with 'police' and flashing lights ordered the vehicle to stop as it neared the aircraft.

"They went for specific boxes. It's clear that they knew what they were searching for."

Another source‚ within the Hawks‚ which is investigating the attack‚ described the heist as a "slick" operation.

"They went for a certain number of boxes. The robbers were assigned to look for and grab certain containers.

"They clearly had good info. They knew how to get into the airport and how to get out‚ which exits to use ... Within minutes they were gone ... clear of the airport.

"The money was in numerous foreign currencies. It was being stored at the cargo section of the airport where high value and high risk cargo such as cash is stored."

Hawks spokesman Brigadier Hangwani Mulaudzi confirmed the robbery.

“A high level investigation has been launched but it is sensitive at this stage‚ so we cannot release any further details‚” he said.

In 2006‚ about R100 million was stolen in an Oceans Eleven style heist at OR Tambo Airport. The gang colluded with three airport employees in robbing an international flight carrying foreign currency destined for FNB and Standard Bank.

And in October 2014‚ robbers‚ armed with semi-automatic rifles‚ rammed a Brinks Global Services bakkie as it left OR Tambo International Airport’s cargo section in Johannesburg. It is believed the money‚ said to include dollars‚ euros and pounds‚ had just been flown into the country when the vehicle was attacked. All the cash was taken. Gunmen rammed the unmarked vehicle‚ damaging it extensively as it left the airport’s cargo section. As several gunmen tried to force the driver and his two crew from the bakkie‚ others removed the canopy‚ breaking open the safe before fleeing with the cash. The guards‚ who were injured in the collision‚ were taken to hospital.

Also in 2014‚ 18 members of a gang that shadowed travellers leaving OR Tambo were arrested. The breakthrough was attributed to the deployment of highly experienced retired detectives‚ an innovation that then national police commissioner Riah Phiyega said was crucial in dealing with high-profile crimes.