MILAN, Italy (AP) _ A sex ring uncovered in Italy that trades in Asian children may be the largest such organization in Europe, operating in more than a dozen countries, Italian authorities said Friday.

The ring was discovered in April but was not made public. Authorities said they revealed it now because indictments were expected soon against a Japanese man and a Chinese woman caught trying to smuggle a 12-year-old Chinese girl to Miami via Milan.

Prosecutor Pietro Forno, who is coordinating the investigation, said Chinese gangs and Japanese mobsters run the operation, with way stations in places such as Italy.

The gang sends the children to the United States through Europe, accompanied by phony parents. Forno said police have evidence that the ring sold at least 15 Chinese children into prostitution in the last month.

Italian authorities have issued warrants for three Italians allegedly working with the ring. Three Japanese linked to the operation have been arrested there, Forno said.

The 12-year-old told police her parents sold her and she was first taken to Bangkok, Thailand, for ``instruction'' in the sex trade.

Milan police said her family, from the Zheijang region of China, sold her for $40,000. Her ultimate destination was the sex trade in Miami, police said, but did not provide details.

In April, suspicious customs agents at Milan's Linate Airport stopped her and her escorts, traveling on false Japanese passports.

This case is not the first indication that Italy is part of the route used by East-West child traffickers. Last November, authorities in Rome arrested a Cambodian man traveling under false documents with four children.

The man, convicted of illegal immigration and receiving stolen goods, is still under investigation on suspicion of involvement in an international sex ring. The Italian news agency ANSA said Friday authorities now believe he is actually Chinese.

Also on Friday, Pope John Paul II issued a forceful call to his clergy to speak out against pedophilia.

``The church must repeatedly recall the need to protect all people, especially the young, being weak and defenseless,'' the pope told bishops from Belgium, a country rocked by a series of pedophile scandals.