This story is being updated as details emerge.

DOWNEY — A man brandishing a gun at the Kaiser Permanente hospital in Downey sent the medical center into lockdown Tuesday, prompting a massive police response and spurring concerns of a possible active shooter on the hospital campus.

The suspect was taken into custody without incident. No shots were fired in the ordeal and there were no reports of injuries.

The incident began at around 11:34 a.m., when reports came in to the Downey Police Department of a disturbance at the hospital. The call was upgraded to a possible active shooter while officers were enroute.

“When our officers arrived on scene, they were directed to a building where the subject was believed to be located,” said DPD Chief Carl Charles.

That building was the Orchard medical building, located east of the hospital proper.

Officers immediately confronted the suspect, who surrendered and was taken into custody without incident.

The suspect was identified as 34-year-old Jesus Chavez of Lynwood.

Chavez had hidden a gun and was unarmed at the time of arrest, authorities said. He was taken into custody just outside the Orchard building after being called out by police.

At a press conference outside the Columbia Memorial Space Center, authorities said Chavez was causing a disturbance when one of the hospital’s security guards contacted him. At this point, Chavez reportedly threw a chair through a window and brandished a handgun.

Witnesses reported hearing 6-7 gunshots but investigators determined Chavez never fired his weapon.

Chavez was booked for making criminal threats and transported to Los Angeles County Jail.

Officials were later able to confirm that Chavez was at the hospital for an appointment, but weren’t able to say why he was carrying a handgun or what initiated his outburst.

A witness, Amber Boughner, told reporters that Chavez was upset over a missed doctor’s appointment.

“He started pounding on the door, saying, ‘I had an appointment at 11 o’clock! I deserve my appointment, where is that B.I.T.C.H. Make her let me in!’ And he just kept pounding, pounding and pounding,” Boughner said.

She said she saw Chavez kick walls and throw furniture out of a window until security arrived.

After the security guard confronted Chavez, Boughner was told to run.

“The security guard came out and he said, ‘He’s got a gun, run,’” Boughner added.

Another witness, Betty Esquivel, said she was in a hospital room when she heard Chavez begin to make threats.

“We started hearing screaming and yelling outside...he was saying, ‘I have a gun, people are going to die,’” she said.

Hospital staff, patients, and visitors were held under lockdown while police cleared the scene. Police cleared four buildings on the hospital campus.

Meanwhile, several local schools and businesses also went into lockdown mode, preventing anyone from entering or exiting.

Several law enforcement agencies responded to the hospital, including the Whittier Police Department and deputies from the Norwalk’s Sheriff’s Station.

The Sheriff’s Department mobilized its Special Enforcement Bureau (SEB), also known as SWAT.

“We want to thank the Sheriff’s Department, their SEB. They had assets here quickly from the surrounding police stations,” said Downey Police Capt. Mark McDaniel. “It was just a great collaborative effort.”

A press conference was held about 2-1/2 hours after the incident began, where it was officially announced that the hospital was secure and there were no injuries.

Questions remain as to how Chavez was able to get onto the property with a weapon in the first place.

That topic was left to be tackled and answered by Jim Branchick, a senior vice president with Kaiser Permanente.

“I couldn’t answer that,” said Branchick. “I’m not sure if he was a member, or a visitor with us. I don’t have any information on that.”

“I’m sure after this is over we will get together with our Downey Police and the Sheriff’s Department to see if we could have done anything better and improve it that way,” added Branchick.

Branchick confirmed there are no metal detectors at the hospital’s entrances.

Still, Chief Charles said that “Kaiser is not any more dangerous than any other facility.”

“Always be vigilant. You need to be aware of your surroundings,” said Charles. “If something seems out of place, call the police immediately…we train for this. We would like to say, we hope that Downey is more secure than most cities, but you always have to be vigilant and this can happen anywhere.”

The hospital had recently undergone active shooter training in April, which was initiated by Kaiser according to officials.

“Hospital staff was great,” said McDaniel. “They had their roles blocking traffic, assisting from a perimeter type setting where the first responders can go in and do their job. It was a good team effort.”

“They’re good partners,” added Charles. “They’re aware of what’s happening in today’s world and they took steps to at least try and be prepared for it.”

The city of Downey utilized its emergency alert system Tuesday to update subscribers on the unfolding situation via phone calls, texts and emails.

Rakdy Khlok, emergency manager for the city of Downey, said the city had not activated its emergency operations center but did open an incident command post.

Evacuees were interviewed by police at Independence Park and then allowed to return to the hospital.

In a statement, Kaiser said it was offering counseling to patients and staff affected by Tuesday’s incident.

“The safety of our patients, employees and physicians are paramount,” the hospital said. “We recognize the stress that can be brought on by a situation like this. We’re offering behavioral health services and support to our patients, employees and physicians who were onsite. All appointments at the facility have been canceled for today.

“We are working closely with law enforcement and ask that all questions about this incident be directed to the Downey Police Department and L.A. County Sheriff’s Department.”

Kaiser and the surrounding streets reopened later Tuesday afternoon.

Eric Pierce contributed to this report.