Belgian authorities say more than 30 people have been detained in a massive police operation aimed at breaking up a vast online car sales racket.

The federal prosecutor's office said that almost 1,200 police backed by drones and helicopters launched a series of raids at seven locations early Tuesday in southern Belgium near the French border. French gendarmes were also involved.

A statement said that more than 30 people were taken into custody on suspicion of racketeering and belonging to a criminal gang.

Prosecutors say that hundreds of people in Belgium were caught up in the racket which involved "embezzlement linked to the sale of vehicles on the internet." Some of the victims were hurt or threatened with violence.