Authorities in suburban New Orleans said Friday they uncovered three teenagers' plot to shoot fellow high school students on campus during the first day of classes.

Lakeshore High School officials became aware of a group calling themselves Day Zero last month when other students contacted administrators. The teens had targeted specific students, but part of the plan was also indiscriminate shooting, said St. Tammany Parish Cpl. George Bonnett.

"Investigators learned the students had a detailed plan for procuring weapons and bringing them to school Monday. They intended to kill any law enforcement officials at the school who tried to stop them and then collect their weapons," police said.

Sheriff Jack Strain said the three 15-year-old boys were being held at a juvenile detention center on charges of conspiracy to commit terrorism and more charges were possible.

"They made no attempt to deny their involvement with the plan and admitted their intentions," police said. "All three were cooperative with investigators."

The boys' identifies have not been released and it wasn't clear whether they had attorneys.

Police would not comment about a possible motive.

Deputies began investigating July 17 and the teens turned themselves in this week. A bond hearing Monday will decide if they can leave the detention center.

Strain said extra deputies will be posted at Lakeshore High on Monday, though authorities believe everyone involved was arrested.

One of the boys is from the Mandeville area, an affluent bedroom community about 25 miles north of New Orleans where the school is located. The other two were from nearby Lacombe, a slightly less affluent and rural.

St. Tammany Parish Schools Superintendent Trey Folse said he did not know how many students reported the threat or how worried they were.

"It alerted them enough to turn it over to authorities, with trust that the people they alerted would look into it and take it seriously."

"I'm very proud of them for stepping up and doing the right thing," Folse said.