A man was hospitalized with life-threatening injuries early Sunday morning after being shot by unknown suspects, police Officer Albie Esparza said.

The incident occurred at 12:12 a.m. in the first block of Ellis Street, near Union Square.

The three suspects, men believed to be in their late 30s, were walking with the victim when they opened fire, Esparza said. The victim was hit in the torso and upper body.

Police are investigating whether the men knew each other, Esparza said. The suspects fled and had not been found as of Sunday evening.

Esparza said the shooting did not appear to be a robbery and is not considered gang-related at this time.

akoskey@sfexaminer.com