(CNN) -- The four teenage boys who were mauled by a brown bear and her cub over the weekend deep in the Alaskan wilderness were recovering Monday.
Two of the teens, participating in a survival skills course, suffered life-threatening injuries, according to Alaska State Troopers, and two had injuries that were labeled "serious, but non-life-threatening." Three others were reported to have minor injuries or exposure-related issues.
Officials at Providence Alaska Medical Center in Anchorage and Mat-Su Regional Hospital in Palmer said Monday that two of the boys have been discharged.
One teen, Sam Gottsegen, had his condition upgraded to good from serious, while another, Joshua Berg, remained in serious condition.
Gottsegen, a Colorado native, spoke to CNN affiliate KMGH in Denver about the brutal encounter.
The teens were on a program run by the National Outdoor Leadership School when they were attacked around 8:30 p.m. Saturday in a remote area about 45 miles northeast of Talkeetna. There were no instructors with the group, which was on day 24 of a 30-day backpacking course to learn about teamwork and wilderness-related skills, according to the Wyoming-based program.
"I thought I was going to die when I was being attacked," Gottsegen told KMGH. "I was so scared."
The station reported he suffered a punctured lung, broken ribs and a severe head wound.
"I looked behind me and the bear was behind me. So, I started running down the hill and it tackled me on the way down," he said.
The teens told state troopers that they were crossing the river in a line when the bears attacked. Those in front got the worst of the assault.
"They were mauled, very severely," said Megan Peters, spokeswoman for the state police. "It was truly an emergency situation."
The boys, ages 16 to 18 and from all around the country, said they followed protocol in calling out to warn the bears and carrying bear spray, according to the wilderness program.
Afterward, the group set up a camp, provided first aid and activated a personal locator beacon, which is used to alert authorities about one's whereabouts in an emergency.
A helicopter was then dispatched, tracking the beacon's signal and finding the teens in a tent around 2:45 a.m. Sunday, said state troopers.
The rescuers determined that two of the victims were too hurt to be safely transported by the helicopter for medical aid. A state trooper stayed on the scene, helping tend to those two, while the others were flown out for treatment at Mat-Su Regional Hospital.
Four hours later, around 6:45 a.m., a better-equipped aircraft arrived to fly out the most seriously injured to Providence Alaska Medical Center in Anchorage, about 150 miles to the south.
A state trooper flew around the area Sunday, trying to locate the animals responsible for the attack. Peters said Sunday night that "we have not laid eyes on the bear and the cub."
CNN's Dana Ford contributed to this report.