NEW YORK, March 19 (Reuters) - The U.S. Justice

Department on Thursday said it took part in an operation

with Germany and Canada to take down infrastructure used by four

major botnets that infected more than 3 million devices

worldwide, including hundreds of thousands in the U.S.

The malicious networks - Aisuru, KimWolf, JackSkid and

Mossad - were used to launch distributed denial-of-service

(DDoS) attacks, with some Department of Defense websites among

the targets, the Justice Department said.

Most infected devices were part of the so-called Internet of

Things, or web-connected appliances like webcams, digital video

recorders, or Wi-Fi routers, the Department of Justice said.

Operators of the botnets carried out hundreds of thousands of

DDoS attacks, targeting computers and servers around the world,

including IP addresses owned by the Department of Defense

Information Network. In some cases, they demanded payments from

their victims, according to the statement.

"Today's disruption of four powerful botnets highlights our

commitment to eliminate emerging cyber threats to the Department

of Defense and its warfighters," said Kenneth DeChellis, a

special agent in charge at the Department of

Defense Investigative Service.

The operation, conducted simultaneously in the U.S., Germany

and Canada, targeted individuals behind the botnets, the

Department of Justice said.

The statement listed nearly two dozen major tech companies

that helped the operation, including Amazon Web Services,

Google, PayPal ( PYPL ) and Nokia, and the PowerOff team of the European

Union's law enforcement agency, Europol, whose operation against

cybercriminals focusing on DDoS attacks has been running since

2017.