A 15-year-old boy was in critical but stable condition Wednesday night after being stabbed three times during a fight in West Valley City.

Just after 8 p.m., the boy was at a friends house near 3700 S. Highlander Street (6885 West), when a friend warned him there might be trouble waiting at school the next morning, said West Valley City police Lt. Dalan Taylor.

"The friend tells him some kids are going to jump him tomorrow at school," Taylor said. "On his way out, he makes a comment, 'Good luck at school.' This sets the boy off."

The 15-year-old began hitting his 18-year-old friend who, in turn, pulled out a pocket knife and stabbed the boy three times, police said.

The boy was stabbed once in the hip and twice in his left side, puncturing his lung, Taylor said. The boy was flown to an area hospital in critical condition, but his injuries were later stabilized.

Police arrested the 18-year-old on suspicion of aggravated assault.