LANCASTER, Pa. (AP) _ A high school student was barred from some school activities after he reportedly mouthed obscenities at television cameras during President Bush's visit to the school.

The student, 17-year-old Steve Petersheim, was in ''preferential seating'' in bleachers behind the president at Conestoga Valley High School on March 22, Principal Harry Wirth said.

Some of his antics, which included blowing chewing-gum bubbles and waving a ''Jackson in '92'' sign after Bush's anti-drug speech, apparently were aired by at least one Philadelphia area television station, Wirth said.

''In this situation he didn't know how to act,'' said the principal, who decided to ban the senior from certain events.

Wirth said the student had been barred from activities ''where we can't control his behavior.'' Those include school assemblies, the senior prom and graduation exercises.

A school secretary logged several calls from television viewers the day of the president's visit complaining about the student's behavior, Wirth said.