HONG KONG (AP) — A multimillion-dollar stash of methamphetamine hidden in electrical transformers being sent from Mexico to Australia has been intercepted at Hong Kong’s airport, authorities said Tuesday.

The 76 kilograms (168 pounds) of crystal meth was found Friday in false compartments in the three transformers, a Hong Kong customs official said. She said the transformers appeared suspicious when they were X-rayed.

“We only saw simple structures but could not see other components that should have been there, such as high voltage cables or coils of wire,” senior Inspector Lam Kai-shan told reporters.

Hong Kong customs estimated the market value of the drugs at $46 million Hong Kong dollars ($5.9 million). The street value would have soared to $68 million Australian dollars ($43 million) in Australia, police there said.

“We are now working together and following every lead to find those responsible for this importation,” Detective Superintendent Timothy Underhill of the Australian Federal Police said in a statement. “Someone in Australia must know about this shipment, and we are very interested in talking to them.”

The Australian statement said Hong Kong officers found the drugs after receiving intelligence from Australian police and other agencies. The air cargo shipment was to be delivered to an address in the western Sydney suburb of Blacktown, it said.