THE HAGUE (AFP) - Thieves used explosives to blast their way into a depot of the security firm Brink's in the Netherlands late on Wednesday, local media reported, with the value of their haul unknown.

No employees of Brink's, which transports cash and valuables, were injured in the heist which happened around 11:00 pm (6am Singapore time) at the US-based firm's building in Best, southern Netherlands, the Dutch ANP agency said citing police.

A helicopter joined 20 police cars at the scene of the crime when the alert was sounded, but the perpetrators had fled, local radio reported.

A search revealed a "suspicious object" which would be examined by explosives experts, police were cited as saying.

ANP also reported that a suspicious car had been stopped on a national highway not far from Best, but that no link had yet been made between the vehicle and the Brink's raid.

Last month, heavily armed robbers disguised as police made off with US$50 million (S$62.5 million) worth of diamonds in a spectacular heist on a Brink's armoured car at Brussels airport in neighbouring Belgium.