HONG KONG : Hong Kong police have raided a crack cocaine laboratory sited in an upmarket apartment and seized narcotics ingredients and drugs worth some $7.6 million, a statement said Sunday. The ingredients were thought to have been imported from Peru and could have been used to produce 40 kilogrammes of cocaine .

This, plus another 10 kilogrammes of suspected crack cocaine found in the apartment, would together have been worth about HK$59 million ($7.56 million), police said in a statement. It was believed to be the first time a luxury apartment had been used as a base for manufacturing drugs, police said.

The four-bedroom flat in Hong Kong 's New Territories measured 1,000 square feet -- large by the city's cramped standards. "What's special about this case is the relatively upmarket apartment... I believe the drug syndicate was hoping to use it as a cover," Superintendent Ng Wing-sze of the narcotics bureau told reporters.

Ng said the operators were probably able to bring the ingredients and other materials to the apartment under the pretext of moving into a new flat . Four men aged between 19 and 38 were arrested, including Hong Kong residents with suspected links to triads and a Peruvian national on a tourist visa, local media reported after the raid last Friday.