Over 565 people in North America and Europe have been arrested in an international sweep aiming at marketing fraud using the internet and other means, the US Department of Justice (DOJ) announced Tuesday.

The international operation, called Operation Global Con, targeted lottery and sweepstakes schemes, offers of nonexistent investments, bogus offers of preapproved credit cards and fee scams similar to the popular Nigerian banking schemes, the DOJ said. Fraudsters used various means, including the internet, telemarketing and mass mail, to target victims, the DOJ said.

The ongoing operation started March 1. The 96 separate US investigations in the operation found 2.8 million victims who suffered losses totalling more than $1 billion, the DOJ said.

The fraudsters believe they can "use modern technology to operate from anywhere in the world with impunity", said US Attorney General Alberto Gonzales, in a statement.

So far, the operation has led to the arrest of 139 people in the US, and an additional 426 arrests in Canada, Costa Rica, the Netherlands and Spain. Authorities executed 447 search warrants in the five countries as part of the operation, and 61 people have been convicted in the US so far, the DOJ said. In addition, the Federal Trade Commission has brought 20 civil actions against 140 defendants in illegal fraud schemes.

Last week, Costa Rican agents, working with US officials, conducted a series of arrests and searches that targeted so-called boiler-room operations. These operations used internet-based telephony and mobile phones to contact prospective victims in the US, purporting to be from nonexistent organisations such as the Sweepstakes Security Commission, to offer nonexistent sweepstakes winnings of as much as $4.5 million, the DOJ said. Victims were expected, in return, to pay insurance fees. Some victims who made the payments would then be recontacted by participants in the schemes, who pretended to be Costa Rican or US customs authorities demanding payment of additional customs fees or taxes.