POCATELLO, Idaho (AP) _ A 14-year-old student at a school for troubled youths pulled a gun on the principal today, and then holed up inside with five other students. The principal escaped unharmed.

Initially, police believed several students and possibly a teacher were being held hostage at The Alternate School by the boy, who fired a shot into a wall or ceiling and demanded cigarettes and alcohol. But nearly three hours later, police Lt. Garry Pritchett said none of the five students with the 14-year-old was considered a hostage. There were no reports of injuries.

He said a psychiatrist was talking to the boy.

The area around the school was cordoned off, and homes within a block were evacuated after the incident began about 8:30 a.m. MDT. A SWAT team was on the scene.

About 90 minutes into the standoff, somebody stepped outside and placed a gun on the ground. A short time later, a person _ it was unclear if it was the same one _ kicked the gun further away.

Pritchett said the 14-year-old, who remained armed with another weapon, had swapped a .22-caliber semiautomatic pistol for packages of cigarettes from police.

Police said the youth had threatened principal Paul Matthews on Wednesday. The boy returned today and pulled a weapon on Matthews, who threw up a table between them and was able to order students to evacuate, Matthews said.

Christopher Williams, spokesman for the Bannock School District, said the incident occurred in the school's multipurpose room. Matthews had just begun his daily routine of explaining what would be on the students' agenda when the boy pulled the gun.

``He (Matthews) told me he had just gotten out about three sentences when the student pulled the gun,'' Williams said.

The school normally has 30-35 students. There are 10 students per class and three teachers and a principal at any one time.

Pocatello, with about 50,000 residents, is home to Idaho State University. It is located in southeastern Idaho, about 200 miles east of the state capital in Boise and 150 miles north of Salt Lake City.