An operation involving 13 countries and aimed at users of “DDoS for hire” services led to the arrest of nearly three dozen suspects last week, said the FBI.

Last week’s law enforcement actions took place in Australia, Belgium, France, Hungary, Lithuania, the Netherlands, Norway, Portugal, Romania, Spain, Sweden, the United Kingdom, and the U.S.

Over five days beginning on December 5, law enforcement agencies conducted 101 interviews and arrested 34 suspects in the sweep, which was coordinated from The Hague in the Netherlands by Europol’s European Cyber Crime Centre (EC3).

Europol, the law enforcement agency of the European Union, assisted participating countries in their efforts to identify suspects—many under the age of 20—by sharing intelligence and analytical support. Actions within the United States were coordinated by the International Cyber Crime Coordination Cell, or IC4, hosted by the FBI in the Washington, D.C. area.

In a press release about the operation, Europol said teenagers who become involved in cyber crimes often have skill sets that could be put to positive use through a career in computer programming or cyber security.

“DDoS tools are among the many specialized cybercrime services available for hire that may be used by professional criminals and novices alike,” said Steve Kelly, FBI unit chief of IC4. “While the FBI is working with our international partners to apprehend and prosecute sophisticated cyber criminals, we also want to deter the young from starting down this path.”

The operation marked the kick-off of a prevention campaign to raise awareness of the risks of young adults being lured into committing cybercrimes.