DEMING, N.M. (AP) _ A boy dressed in camouflage shot and critically wounded a 13-year-old female classmate in the lobby of their middle school Friday.

The boy also pointed a pistol at the principal and assistant principal, who told him to ``stay cool,'' Superintendent Carlos Viramontes said. He was taken into custody shortly after the 12:45 p.m. shooting at Deming Middle School.

The girl, Araceli Tena, was in critical condition at Thomason Hospital in El Paso, Texas, with a gunshot wound in the back of the head, a hospital spokeswoman said. She was taken by ambulance to the hospital about 100 miles east of Deming.

Police refused to comment on the boy, also 13. No charges had been filed.

Viramontes said school officials had ``heard a lot of stories'' but knew of no motive for the shooting at the only middle school in the farming and ranching town of about 15,000 about 33 miles north of the Mexican border.

``Right now, the only relationship that we know of is the fact that they were students here at the middle school. ... We don't know if there was any association between the victim and the suspect,'' Police Chief Michael Carillo said.

When police arrived at the school in response to a 911 call, they confronted the armed student in the lobby. They ordered him to put down the small-caliber pistol, and after about five minutes, he reluctantly put it down, Carillo said.

No other students were hurt, and only one shot was fired, he said.

Some students were locked in classrooms until police announced the school was safe, and several parents picked up their children after hearing about the shooting.

The school district had established a safety plan for just such a situation last year following the shootings at Columbine High School in Colorado, ``hoping we would never have to use it,'' Viramontes said.