Police must cooperate across borders to keep children safe from child abusers and Internet pornographers, U.S. first lady Laura Bush said Wednesday at a Paris conference on missing and exploited children.

French first lady Bernadette Chirac hosted the one-day conference at the Elysee Palace, 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 fight the problem in the United States, such as the Amber Alert system mobilizing 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, allowed authorities to 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 also urged international cooperation on 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 the abused girl to North Carolina, and the relative who hurt her is serving a 100-year sentence.

The relative had 175,000 images in his computer, and police used them to track down child abusers in South Carolina, Texas and Britain.

"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, Virginia. 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.

Other participants in the conference included Nobel Prize-winning writer Elie Wiesel, who spoke of society's responsibility to protect children, as well as Ronald Noble, secretary general of Interpol. The European Union's justice and home affairs commissioner, Franco Frattini, as well as EU Information Society Commissioner Viviane Reding, also took part.