A Brinks armoured truck lost control on a Toronto highway ramp Sunday afternoon, rolling over and trapping three guards and numerous bags of cash inside its vault.

The rollover occurred on a ramp between Highway 427 and 429 at about 2 p.m. The truck came to rest at the bottom of an embankment, trapping two guards in the back with the cash.

Rescuers couldn't cut them free, break the locks or look inside -- resorting to breaking through the vehicle's bullet-proof glass with a heavy sledge hammer and sending a paramedic inside the vault.

The driver suffered serious injuries and was taken to Sunnybrook hospital. The two men in the vault were not seriously hurt. They suffered cuts, bruises and back injuries, according to Glen Gillies of Toronto Emergency Medical Services. They were also taken to hospital.

"I don't know whether they were restrained or not, but they look like they went for quite a ride," he told CTV Toronto.

EMS officials said breaking through the vehicle's burglar-proof plating -- designed to withstand gunfire and explosions -- made for one of the most difficult rescues they have ever executed.

Gillies said he had "never had a Brinks truck before."

"We have had our difficult extrications but this one presented a challenge," he added.

With the guards off the job, guarding the bags of money left inside the wreck was up to the police. They spent Sunday evening on the scene watching over the valuables and trying to determine what caused the crash.

Brinks eventually towed the vehicle to its facility, where it will crack open the safe and transfer the cash to another truck.

With a report from CTV Toronto