The National Center for Missing & Exploited Childen said Friday that Ma Jingjing, "... missing from @reagan_airport in Arlington, #Virgina has been found safe! Thank you for sharing her poster, without your help we wouldn't be able to bring you this fantastic news!"
The FBI is now taking over the investigation. Details about what happened have not been released and police have not said whether an abduction actually occurred.
Jingjing had been last seen about 8:15 a.m. Thursday at Ronald Reagan Washington National Airport in Arlington.
Metropolitan Washington Airports Authority Police Chief David Huchler said late Thursday that she was believed to have left the airport "without force" with an unknown woman.
Airport surveillance video showed the woman helping the girl put on some clothing, and when they left together, the 12-year-old was wearing a white T-shirt, blue jeans and a black jacket.
Huchler said Jingjing and the woman got into a white, late-model Infinity QX60 with unknown New York tags. The vehicle was being driven by an unknown man.
Huchler said the girl was approached earlier by two individuals as her tour group visited the World Trade Center in New York. It is unclear if the individuals from the airport are the same as the couple in New York, Huchler said.
Jingjing had been traveling in the United States since July 26 with a group that was visiting schools and sightseeing, Huchler said. The group was en route to California after visiting New York. Sometime after arriving at Reagan Airport, Jingjing became separated from the group, Huchler said.
Another student notified chaperones that she was missing as the group proceeded through the airport's security check-in, he said.