U.S.government authorities have arrested 60 people in the United States on charges they were part of a global network of child pornographers.

Attorney General Michael Mukasey said the long-running and far-reaching case began with a single lead from Australian police in what became known as Operation Koala in Europe and Operation Joint Hammer in the United States.

"From that initial horrible discovery, the investigation grew to reveal connections in nearly 30 countries around the world," Mukasey said, standing beside justice officials from France and the Czech Republic. France is the current head of the European Union to be followed Jan. 1 by the Czechs.

By scouring the suspects' e-mail accounts and computers, authorities in Europe, Canada, and the United States have been making spin-off arrests for more than two years.

This week, U.S. authorities charged a man in California with inducing an 11-year-old girl to engage in sexual conduct and with creating molestation images to distribute.

Authorities said the investigations are continuing as individuals in one child pornography network lead to other such networks.

The U.S. arm of the investigation has also led to the identification of 11 child victims, officials said.