Police raided 12 houses across the U.K. (search) in the early hours of the morning Tuesday, arresting the suspected kingpins in a multimillion dollar human trafficking ring.

The Press Association — the U.K.'s national news agency — and other news outlets reported Tuesday that police officials allege the group was responsible for smuggling tens of thousands of mainly Turkish Kurds into the United Kingdom over the last few years.

Scotland Yard (search) said the raids were the culmination of a two-year investigation, codenamed Bluesky. Over 200 officers and co-operation from law enforcement agencies in five other European countries were involved.

In total, 19 people were arrested in the raids. Eight suspected members of the smuggling network were among those arrested, according to the news reports.

The gang is believed thought to have lured thousands of economic migrants from eastern Europe to Britain with the promise of a better life.

Each would have paid $5,000 and $9,000 to be smuggled in from the Balkans (search). Most would be moved across mainland Europe in groups of 20 to the northern coastal ports. Once there, police said, they would remain in safe houses until the time was right for them to be smuggled into Britain in secret compartments hidden in trucks, cars, or ferries.

In Britain, most would take low-paid, menial jobs in the capital's black market economy.

The network's ringleaders are thought to have come to the United Kingdom from Turkey (search) as asylum seekers, the Press Association reported.

The raids were carried out at five houses in Enfield, two in Bexleyheath and one each in Barnet, Haringay, Tower Hamlets, Hackney and Hammersmith.