OAKLAND — A man who underwent surgery Monday morning after being stabbed at a fitness center near Lake Merritt early Monday was recovering Tuesday and was in stable condition, authorities said.

The name of the 32-year-old victim, who was stabbed in the arm, was not released. It was not clear if he was an employee of Fitness SF, 600 Grand Ave., or had been working out there.

A 49-year-old man was arrested about 20 minutes after the attack, which happened around 10:25 a.m. Monday. He was undergoing psychiatric evaluation and has not been booked into jail, authorities said.

Authorities said the suspect confronted the victim outside the center and began yelling and screaming at him. When the victim went back inside the suspect followed him and stabbed him with a sharp object, possibly a knife, authorities said.

The suspect fled and was arrested a short distance away in the 2800 block of Lakeshore Avenue after a brief standoff, police said. Police have not determined if the two men knew each other.

The fitness center remained opened while police investigated.