A gunman opened fire at a popular hang-gliding park Monday night, injuring two people before turning the gun on himself in what appeared to be an unprovoked attack.

The suspect had been walking around the parking lot at Fort Funston in southwest San Francisco trying to pick a fight around 7 p.m. before shooting the two victims, who apparently had just finished hang gliding, witnesses said.

The injured men were taken to a nearby hospital, where one was listed in critical condition and the other was described as stable, according to the Golden Gate National Recreation Area Park Police.

"The shooter's dead," said police spokesman Rich Weideman. "We don't know the circumstances."

Rico Tecsom, 38, of Daly City, said he just finished walking his dog when he saw the suspect approach the two victims and begin what appeared to be a non-confrontational conversation before suddenly pulling out the gun.

"I froze," Tecsom said. "When my dog took off, that's when I realized I should, too. I started running."

Two guns, both believed to belong to the suspect, were found near his body. He was not immediately identified.