Air Canada has been sued by Miami-based transport and security services provider Brink's, which alleged the airline of "negligence and carelessness" related to a gold and cash heist at a Toronto cargo facility in April, a court filing showed.

Brink's claimed that the airline allowed an unidentified individual inside its cargo facility at the Toronto Pearson airport and released about 400 kilograms of gold and $1.95 million in cash upon being presented with a fraudulent waybill.

According to the lawsuit, Brink's was hired by Swiss bank Raiffeisen Schweiz and precious metals refining company Valcambi to move the cash and gold from Zurich to Toronto.

A police investigation is ongoing but there have been no arrests or convictions and the shipments have not been recovered, the lawsuit said.

Brink's alleged that Canada's largest airline failed to enlist reasonable and appropriate security measures and protocols to prevent the heist, according to a statement of claim filed in Canada's federal court on Oct. 6.

Air Canada did not immediately respond to Reuters' request for a comment.

Brink's claimed that Air Canada is liable for the full amount of the value of shipments, which would be worth about $17 million.

(Reporting by Shivansh Tiwary in Bengaluru; Editing by Shilpi Majumdar)