A hiker died Monday after he was attacked by a swarm of bees and fell about 150 feet off a cliff at Camelback Mountain in Phoenix.

Three adult men between the ages of 18 and 20 had been hiking on Echo Canyon trail in a section of the mountain called Ice Box Canyon in the afternoon. The hikers were found off-trail in an area known mainly for free climbing.

At around 3:45 p.m., the bee attack began. One hiker tried to run away and fell 150 feet to his death. A hiker who was not in the group witnessed him falling off the cliff and immediately called 911.

"The other two males hunkered down in an area and covered their nose and mouth," Public Information Officer Larry Nunez of the Phoenix Fire Department told ABC News.com.

Fire officials said the two hikers were airlifted out of the area by a Phoenix Fire and Police helicopter after they'd been stung more than 300 times.

"They were taken immediately to the hospital and are now recovering," said Nunez. The search and rescue operation was "very difficult" because of the location and circumstances, he said, adding that rescue workers had to "wear a bee suit during the hoist operation."

The hiker's body has since been recovered and his family notified, but the names of the hikers have not been released. While officials said bee attacks were not common, they'd seen them in the past, particularly where bees tend to gather in spots.

"If you are being attacked by bees, do not wing your arms and swat at them, but be sure to cover your nose and mouth," said Nunez. "What we ask folks is that if they hear bees, steer clear of them, and if you see something dangerous, turn around."