SAN FRANCISCO (AP) _ The bodies of two students who were on a school camping trip have been found at the bottom of a 67-foot ravine in a state forest nearly 150 miles south of San Francisco.

The teenagers were identified as Mikhail Nikolov and Vladislav Bogomolny, both 17-year-old students at the Urban Pioneer Experiential Academy, a charter high school in San Francisco.

Investigators have not determined whether the boys accidentally slipped or were somehow forced off the cliff, but their injuries were consistent with a fall from the top of the ravine, the sheriff's department said.

The bodies were removed from the Arroyo Seco gorge late Wednesday and their families were notified. Arroyo Seco is located about 140 miles south of San Francisco.

The boys were part of a group of 27 students and eight adults from the academy who left Feb. 24 for Los Padres National Forest, said a spokeswoman for the San Francisco Unified School District. They were due back Thursday.

It was not immediately known when the students were reported missing. Calls to police were not immediately returned Thursday.

The director of Urban Pioneer appeared distraught Wednesday at an emergency meeting of San Francisco's school board.

``As you can guess, this has been a very hard day for me,'' Wayne MacDonald said. ``It has been confirmed that two of our students are dead. I thought I'd never say that.''

Urban Pioneer opened in September and has 150 students. School officials said police vans were dispatched to bring the rest of the children back to the city.