The FBI warned Monday that more than 300,000 Internet users worldwide could lose their Web access starting in July following a multi-million-dollar scam.

But users can breathe a sigh of relief as a solution is just a few clicks away at dcwg.org, a website the FBI created so people could check whether they have been infected with malware and remove any malicious software.

Six Estonians were arrested on charges of fraud in November after a two-year FBI sting -- Operation Ghost Click -- into the group's practice of infecting computers around the world with their DNS Changer malware, which made the machines vulnerable to viruses. A Russian collaborator remains at large.

The Federal Bureau of Investigation estimates that up to 568,000 computers were infected with the malware, which redirected users to fraudulent websites. Investigators say the alleged swindlers made up to $14 million under the scam that involved online advertising.

"We replaced the bad service by a clean service so that way people's Internet access remained intact," FBI spokeswoman Jenny Shearer told AFP.

"But there's still a concern that there could be several hundreds of thousands of people in the US but also in EU and in India whose computer might be relying on the clean service," which was never intended as a permanent solution, she added.

Shearer said at least 300,000 people could still be affected.