ISTANBUL, Feb. 1 (Xinhua) -- Turkish police on Friday launched the country's biggest operation against illegal online gambling sites, seeking the detention of at least 394 people.

The Istanbul cybercrime unit ordered the detention of the suspects in 40 provinces across the country for violating the law on online gambling and gaming regulations, Daily Sabah reported.

During the operations, 42 million Turkish liras, or 8 million U.S. dollars, were seized in cash, the report said, noting the sites have generated some 3 billion liras (577 million dollars) in illegal proceeds.

Police have examined 4,345 bank accounts belonging to 849 individuals and 72 companies as part of the investigations, the state-run Anadolu Agency said.