San Francisco ? Authorities searched for a 12-year-old Chinese girl Friday who was reported missing from a youth tour group that had an overnight layover in the Bay Area before heading to a space camp in Alabama.

Yukun Jia flew from Beijing and cleared customs around 2:10 p.m. Thursday. She was reported missing around 5 p.m. by the adult leaders of her group, said police Sgt. Larry Ratti.

After arriving at the airport, the group toured nearby Stanford University. When adults counted heads before the group boarded the bus, they noticed Jia was missing, Ratti said.

It was not immediately clear whether she disappeared at the airport or at Stanford, but tour leaders told police that Jia’s luggage was not loaded onto the bus at the airport. The girl had no known history of running away and no known relatives in the area, Ratti said.

The possibility that the girl is seeking to defect from China hasn’t been ruled out, Ratti said. The girl speaks Mandarin Chinese and very little English, he said.

The California Highway Patrol issued a statewide “Amber Alert,” which helped authorities rescue two missing teenage girls Thursday. Ratti said an alert typically is not issued unless authorities confirm an abduction, but authorities offered to distribute Jia’s description anyway.

“The CHP said if you’ve got that info, why don’t we put it out there,” Ratti said.

The group planned to leave Friday to attend the U.S. Space & Rocket Center’s space camp in Huntsville, Ala. Center spokesman Al Whitaker said the camp frequently welcomes visitors from around the world.