Anchorage: A 16-year-old runner who was fatally mauled by a black bear during a weekend mountain race in Alaska reportedly called his brother while he was being chased by the animal in a rare predatory attack, officials say.

A mine contractor was killed in a separate bear attack in the state a day later. 

Patrick Cooper, 16, died on Sunday while competing in the Robert Spurr Memorial Hill Climb south of Anchorage. He had become lost during the race after somehow veering off the trail.

At one point he reportedly placed a frantic phone call to his brother saying he was being chased by a bear. His brother then alerted race organisers who began searching for the boy.

A couple of hours passed before emergency workers found the boy's body being guarded by the 113-kilogram bear, which was then shot by rangers before it ran away, race organiser Brad Precosky said.

The boy's body was flown from the scene on Sunday, Alaska state troopers said. Fish and game department spokesman Ken Marsh said park authorities were scouring the area for the bear.

Sunday's attack was believed to have been a rare predatory move, not a defensive action such as when a female bear will protect her cubs, he said.

"It's very unusual," Mr Marsh said of the mauling. "It's sort of like someone being struck by lightning."

An underground gold mine contractor taking geological samples at Pogo Mine was killed and another was injured when they were set upon by a black bear about 480 kilometres north-east of Anchorage on Monday.

Alaska state troopers and federal mine officials are investigating the mauling.

Before the two incidents, the last fatal mauling in Alaska occurred near Delta Junction in the state's interior in 2013, when a man was killed by a male black bear, Mr Marsh said.

The last fatal bear attack in the greater Anchorage area was in 1995, when two people were killed in the Turnagain Arm area by a brown bear protecting a moose carcass, he said.

AP