As shots rang out, she answered call

Inside the soldier readiness facility on this Army post, Major Nidal M. Hasan opened fire with two pistols, one of them semiautomatic, officials said. The gunfire was continuous, methodical, and well-aimed. Unarmed soldiers who had been waiting for medical appointments scattered or dropped to the floor.

Hasan, an Army psychiatrist, shouted “Allahu Akhbar!’’ - “God is great’’ in Arabic - and emptied as many as six magazines during the rampage, according to Lieutenant General Robert Cone and other Army officials.

Munley, 34 years old and trained in tactics developed in the wake of the Columbine massacre, raced toward the gunfire. She arrived at 1:27 p.m., about four minutes after the first 911 call, as Hasan was fleeing the building, according to official accounts.

Munley rounded a corner and fired twice at Hasan. He fired back and charged at her, according to the accounts. Munley dropped to the ground in a protective position and continued firing.

At some point, Hasan began to fumble with his gun. “He’s reloading,’’ someone screamed, according to an officer on the scene.

In the exchange, Munley was struck in both thighs and one wrist. Hasan was shot four times.

Hasan, 39, is hospitalized and remained on a ventilator yesterday. He is suspected of acting alone in a rampage that killed 13 people and wounded at least 30 others.

Investigators were searching for a motive yesterday, but relatives said Hasan was unhappy about his upcoming deployment to Afghanistan.

By some accounts, other police officers might also have fired at Hasan. Army officials, however, said credit for stopping the gunman belonged primarily to Munley, who remained hospitalized yesterday in stable condition.

Her actions quickly made her a hero to colleagues and strangers alike, as online discussion groups, police union officials and others praised her decisive role in felling the alleged gunman.

“She walked up and engaged him,’’ Cone said. “It was an amazing and an aggressive performance by this police officer.’’

When the shooting stopped, Hasan was carried out and laid on the ground in front of the center with some of the other severely wounded soldiers.

Medics pulled off his camouflage top and began to treat his wounds, said Sergeant Andrew Hagerman, a military police soldier at the scene. Hasan and three other badly injured soldiers were flown by helicopter to Scott & White Hospital in nearby Temple, Texas.

Soldiers loaded other victims, several shot multiple times, into cars and sped them to Darnall Army Medical Center, about one mile away, witnesses said.

“It was very moving. They were carrying their wounded buddies into the emergency room,’’ said Janet DiPalma, a nurse at the facility.

At Darnell, some troops ripped off their camouflage tops and fashioned T-shirts into makeshift bandages and tourniquets, said Sergeant Howard Appleby, who had gone to the hospital to meet with a psychiatrist for post traumatic stress and quickly found himself helping with the wounded.

Several of the wounded soldiers lay on their stretchers and prayed. Others asked for cellphones to call loved ones to let them know they were wounded.

“It was a lot of rounds fired,’’ said Major Stephen Beckwith, a doctor at the facility. “It was hard to imagine one person did all that shooting.’’

Most of the wounded had been shot two or three times in the chest, stomach or neck, said Major Stephen Beckwith, a doctor at the facility, who like many others at the hospital said he had dealt with similar mass casualties while serving in Iraq.

“I was in Iraq for 15 months. When you are in Iraq you are prepared for this to happen,’’ he said.

Cone called Munley “one of our most impressive young police officers,’’ and said she responded to the shooting rampage just as she was trained to do.

“If you act aggressively to take out a shooter, you will have less fatalities,’’ Cone said.

No one answered the door yesterday at Munley’s house.

Neighbor Brooke Beato said Munley is passionate about her job, and she wasn’t surprised to learn of her heroic actions.

“There should be a parade for her all the way to her front door,’’ Beato said. “There could have been a lot more lives lost. It could have been someone else there first, someone not as well trained, not as brave.’’

Another resident, Amanda Maben, offered a similar sentiment. “She’s a hero and she’s my neighbor,’’ she said.

Also yesterday, more than a dozen Facebook groups popped up in support of Munley. “Sgt. Kimberly Munley: A Real American Hero!’’ had 560 members by late afternoon.