Two of the victims were in a critical condition, police in Phoenix, Arizona, said.

The shooting at South Mountain Community College was part of a running dispute between the suspect and one of the victims, said Sgt Andy Hill of Phoenix Police Department.

"This was not a random shooter going around the campus shooting," Sgt Hill said, noting that two of the injured people were struck by stray bullets.

"I saw someone get punched and then I heard three shots after that," said student Yessenia Lara, 18. "Everybody basically ducked, and the shooter got away." She said the victims were yelling in pain.

The suspect was identified as Rodney Smith, who police said was a former student at the college.

Smith, 22, was arrested at an address a few miles away within half an hour of the first emergency call about the shooting, police spokesman Reuben Gonzales said.

Also arrested at the home were Smith's parents and three other people on charges of interfering with an investigation and failure to obey a police officer.

A 25-year-old man and a 22-year-old woman were in a critical condition and a 17-year-old boy was in a stable condition.

College spokesman Robert Pryce said about 20 to 30 people were in the computer lab during the shooting and as many as 300 people were on campus. The computer lab is open to the public.