Interpol says some 200 people have already responded to its public appeal to help identify a man shown sexually abusing children in internet images.
The suspect is said to be of European origin, and aged 35 to 40
It says the messages were received in the 12-hour period after the appeal was launched on Monday.
The suspect appears in about 200 images with 12 different boys. The photos were taken in Vietnam and Cambodia.
They were digitally altered but police computer experts produced four identifiable images.
Interpol says the man - whose identity and nationality are still unknown - is a danger to children while he remains at large.
Names and sightings
"We have a lot of response and they are coming from all over the world," Anders Persson, a Swedish policeman in charge of Interpol's child abuse images team, was quoted as saying by the Associated Press news agency.
He said that some of the public messages had detailed information such as names and addresses, while others were just names or sightings of people met on holiday.
Mr Persson added that Interpol - which has 186 member states - was forwarding the information to the countries concerned for further police checks.
He did not say whether any of the public messages had given Interpol any clues as to the possible whereabouts of the suspect.
Interpol launched its unprecedented global public appeal on Monday, after trying "all other means to identify" the man.
"We are now convinced that without the public's help this sexual predator could continue to rape and sexually abuse young children whose ages appear to range from six to early teens," Interpol chief Ronald Noble said:
The first pictures of the man were found three years ago in Germany and the search for the suspect had been codenamed Operation Vico, Interpol said.
The pictures had been manipulated to disguise the man's face with a swirl pattern, but computer specialists at Germany's federal police agency, the BKA, worked with Interpol's human trafficking team to produce identifiable images.
They show a man with slightly receding dark hair, aged 35 to 40 years old.
Interpol maintains a database of 520,000 images of child sex abuse submitted by 36 member states.
Using sophisticated software, investigators have identified and rescued nearly 600 victims from 31 countries.