Ten people have been arrested in France, Italy, Portugal and the United States in an Italian-led inquiry into an online child porn network operating in 28 countries, investigators said Thursday. The prosecutor's office in Florence headed the probe, nicknamed "Operation Nanny", in coordination with the European Union's judicial cooperation unit Eurojust, and 112 other people are also being investigated. The suspected head of the network is a 52-year-old Italian man. The one-year investigation found photos and videos of children under the age of 11 and even babies. The network had a total of 700 members around the world including in Argentina, Belgium, Chile, Israel, Mexico and Saudi Arabia. The network's main server was in the US city of Dallas, Texas. Investigators said they managed to trace the IP addresses of computers from which the paedophile material was being sent and identify the owners. Apart from the 700 network members, thousands viewed the material.