Police in three countries have arrested 17 people and seized nearly 2 tons of drugs in connection with what Australian authorities say was an effort by organized crime groups to transport large amounts of drugs into Australia.

Australian Federal Police said 10 people in Sydney, five Australians in Dubai, United Arab Emirates, and two people in the Netherlands were arrested Tuesday as part of an investigation into what police say were two interlinked crime syndicates operating across the three countries.

Officials in the Netherlands seized 1.8 tons of MDMA, also known as ecstasy, 136 kilograms (300 pounds) of cocaine and 15 kilograms (30 pounds) of crystal methamphetamine, all bound for Australia. The drugs were worth around 810 million Australian dollars ($640 million).