BROWNSVILLE, Texas — The morning bell had rung and students were settling into their first period classes Wednesday when a voice broke in over the public address system: Cummings Middle School was on lockdown.

As teachers initiated the school's emergency procedures, locking their classroom doors, turning off the lights, drawing the shades, and calming their confused and worried charges, some students took comfort by climbing under their desks. One boy said he heard police officers charge down the hallway and shout "put down the gun." Then shots, three of them, most students said.

The officers shot and killed an eighth-grade student who pointed a handgun at them, Brownsville police detective J.J. Trevino told The Associated Press. The 15-year-old, whose name police and district officials didn't immediately release, was taken to a local hospital and pronounced dead.

Investigators were trying to determine why the boy had the gun at school and whether he fired any shots, Trevino said.

"It's still under investigation, as far as how he came about to bringing the weapon or if he encountered anybody or anything else," he said. Police scheduled a news conference for later Wednesday to discuss the case.

News of the incident spread quickly through this border city on Texas' southern tip, and frantic parents rushed to the downtown school to find their children.

Jade Rodriguez, an 11-year-old sixth-grader, said the experience was frightening.

"I was nervous. I was under the desk," she said. Administrators said the school would be closed on Thursday but that students could attend classes at a nearby elementary school if they wished. Jade said she too afraid and would stay home.

With police and district officials saying little about the shooting in its immediate aftermath, those details that did trickle out came mainly from students at the 750-pupil school.

Robert Valle, 13, said he heard police running and yelling "put the gun down" before the gunfire erupted.

Gina Rangel, 14, was in her first period class in the gym when the school went on lockdown. She said friends who were closer to the shooting said the boy was near the cafeteria and had said he was going to kill everyone.

"I am worried (about the school's safety) because if this happened once, kids imitate," said her mother Irma Rangel.

District officials said administrators were quick to call police after the student brandished the handgun at around 8 a.m., shortly after first period classes began. Drue Brown, a district spokeswoman, issued a statement in which she said the officers shot the student after he "engaged" them.

Parents and family members who got to the school quickest were able to retrieve their frightened children, but some who arrived later found the street outside the school lined with squad cars and blocked off. About two hours after the shooting, dozens of frustrated parents and relatives flooded out of the park pavilion without their children after school officials announced that all remaining children had been bused to a high school and could be picked up there.

Julie Tomalenas waited for an hour to pick up her 13-year-old sister before being told of the relocation.

"It was very stressful not knowing if she was OK, where she was, when we could see her again," Tomalenas said.

The lockdown was lifted about two hours after the shooting, but the students and employees were relocated while officers investigated at the school, Brown said.

Trevino said investigators hadn't determined whether the student fired any shots, and he said officers had no information on why the student might have had the gun on him.

"It's still under investigation, as far as how he came about to bringing the weapon or if he encountered anybody or anything else," Trevino said.

Associated Press writers Diana Heidgerd and Danny Robbins in Dallas contributed to this story.