PARIS – Laura Bush said at a gathering of first ladies yesterday that police must work with counterparts in other countries to keep children safe from abuse and Internet pornographers.

French first lady Bernadette Chirac hosted the one-day conference on missing and exploited children, which brought together first ladies including Suzanne Mubarak of Egypt and Lyudmila Putin of Russia, as well as Queen Silvia of Sweden and Queen Paola of Belgium.

Mrs. Bush briefed participants on efforts to protect children in the United States, touting the Amber Alert system that mobilizes TV, radio and highway signs to get word out whenever a child goes missing.

“So far, Amber Alerts have saved more than 300 young lives in the United States, and similar programs are now saving lives in countries across the globe, including France,” she said.

France’s new system, modeled on the U.S. alerts, helped authorities track down three missing children last week.

The women proposed that the system be extended throughout the European Union, so all its member nations are alerted when a child goes missing.

Mrs. Bush said the U.S. alert system helped increase the percentage of missing children found to 94 percent today, compared to 62 percent in 1990.

The first lady also urged international cooperation in fighting online child pornography. She cited the case of a police officer in Denmark who found child pornography online and alerted Interpol. Eventually, the FBI traced images of an abused girl to North Carolina and a relative of the child was sentenced to 100 years in prison.

The relative had 175,000 images on his computer, and police used them to track down other child abusers.

“Because one person in Denmark tipped off Interpol, four children in the United States were saved,” Mrs. Bush said.

The conference was a meeting of the honorary board of directors of the International Center for Missing ‘ Exploited Children, based in Alexandria, Va. A study by the group examined all 186 Interpol member countries and found that up to 95 of them had no laws on child pornography, while 136 of them do not consider possession of child pornography a crime.

“This is a global phenomenon, and if we do nothing, it will become a huge epidemic,” Mrs. Mubarak said.