A vicious fistfight involving seven men in the Mission district early Tuesday left one of the men fighting for his life at a local hospital.

About 2 a.m., police said, officers responded to reports of a brawl that possibly drew up to 20 people at the bustling intersection of 16th and Valencia streets.

When police arrived at the scene, they reportedly found two men who had been beaten up. A 46-year-old man was lying on the ground unconscious and unresponsive, Officer Albie Esparza said, while a 44-year-old man was bloodied up but OK. Both were taken to San Francisco General Hospital for treatment.

The unresponsive man was still in critical condition as of Tuesday afternoon, Esparza said.

Investigators have not said what started the fight, only that five suspects who are being sought in connection with the incident had fled before officers arrived.

People who were in the area, including two taxi drivers, have been interviewed, Esparza said, and video footage from the security cameras in their cabs and on buildings in the area is being reviewed.

maldax@sfexaminer.com