Patrick Henry High School in north Minneapolis was searched room by room, top to bottom, and armed police escorted groups of students out of the building over three hours Tuesday after someone believed to have a gun ran inside.

Parents waited anxiously until they made contact with their children.

Map: Patrick Henry High School was put on lockdown Tuesday, after a person with a gun was seen stepping off a bus nearby.

A “code yellow” was called about 3:30 p.m., about 20 minutes after the school day ended, quickly followed by “code red,” meaning students and staff members were ordered to lock classroom doors, shut off lights and pull curtains.

Hundreds of students, teachers and coaches were still scattered throughout the building for after-school activities and meetings.

Jania Kloeppel, 16, said she was in the auditorium when the alarm came over the intercom. She and the students with her hid in a prop room until police reached them.

“It’s unnerving, but at the same time it’s what’s been going on in this country,” she said. “In the back of my head I kind of knew something like this was going to end up happening, but I didn’t think I was going to get caught in it.”

Police said the male fled to the school and entered through a side door after trying to get on a Metro Transit bus. He left the school minutes later, police said in a news release Tuesday night.

Police spokesman John Elder said no shots were fired, no one was injured and no arrests were made.

“All indications are that the person was fleeing from police that were alerted to the fact that he was attempting to board an MTC bus with a handgun or a weapon of some sort,” Elder said.

“We don’t believe this is at all tied to the school at this time, so there’s no reason to believe there was any ill will or malice toward anybody in that building,” he said.

Early in the incident, dispatchers said that two teams of officers were sweeping the building for signs of the male, who was described as wearing a beanie and a puffy jacket. Once the all-clear in each room was given, students were escorted out.

Police said 200 students and staff were escorted out of the building. Students were taken to a Metro Transit bus, then reunited with parents.

Minneapolis Public Schools posted on Twitter that the incident occurred when “an unauthorized visitor ran into Patrick Henry High School.”

“There were concerns about the possibility of a weapon so Minneapolis Police was called,” district officials wrote.

Dozens of police officers, searched the school or stood outside. No weapons or other suspicious evidence was found, police said.

Suspect seen on bus

Sierra, a 10th-grader at Patrick Henry who did not want her last name used out of concern for her safety, was on 44th Avenue N. getting on a No. 5 bus Tuesday afternoon when she saw the suspect, who she described as a male in a gray puffy jacket, standing on the bus.

A police officer got on the bus and told everyone to put their hands up.

The officer grabbed a child in a red jacket and took him off the bus, then patted him down. He did not have a gun, but the male in the gray puffy jacket got off the bus.

Sierra said she did not see a gun but said the male had his hand around what appeared to be a gun in the right front pocket of his coat.

Sierra said a week ago, the same person was outside the school with a gun, showing it around. He was told to get away from the school.

Dora Hill, Jania’s mother, said she went to school about 3:30 p.m. for a meeting about college preparation for her daughter, who is a junior, when she heard over the intercom: “Code red, turn out the lights, shut the door and close the curtains.”

The police did a search of the first floor, where she was, and let those people leave the school. Her daughter remained in the school on the third floor.

She estimated 200 to 300 people were still in the building when the lockdown started.

Hill said police were searching every closet, every bathroom, every stall. “This is happening at every school. It’s not cute, it’s not funny,” she said.

‘Hysterical, scared’

Nicole Martin waited outside for her daughter, Savannah, for more than two hours. The 15-year-old freshman was in the gymnasium with friends.

“She was hysterical, scared,” Martin said of her daughter. “They didn’t know what was going on yet. She was frantic.”

Martin said it’s a situation that you don’t ever think will happen to your own kids. “It just goes to show it can happen anywhere, good schools, bad schools,” she said.

Martin said she isn’t sure what to tell her children about going to school Wednesday.

“It’s going to be tough,” she said. “You think you’re sending your kids to school safe, and they’re not safe.”

Schools nationwide are on high alert in the wake of several recent mass shootings, including earlier this month when 19-year-old Nikolas Cruz opened fire in his former high school in Parkland, Fla., killing 17 people.

Staff writer Libor Jany contributed to this report.