Six people were wounded in a shooting outside a club in Houston early Sunday morning, police said.

One man was hospitalized in critical condition, Houston Police Chief Troy Finner said. Five other people in their late twenties and early thirties were wounded and in stable condition.

No arrests had been made as of Sunday afternoon. Police said they were unsure how many people opened fire.

An altercation inside the club spilled outside, Finner said, leading to gunfire.

Police said there was surveillance video from the scene that would be part of the investigation. Back in February, a woman was struck by a stray bullet at the same address, according to local ABC affiliate KTRK. The building has changed hands since then; at the time it was a Pizza Parma.

The violence in Houston came less than 48 hours after nine people were wounded in a separate mass shooting in San Francisco. Eight men and one woman were shot at a party around 9 p.m. Friday in the city’s popular Mission District, police said.

While eight of the victims suffered non-life-threatening injuries, one man was hospitalized in critical condition, according to authorities.

San Francisco police called the incident a “targeted and isolated” attack. Witnesses described a chaotic drive-by shooting in which a man riding in a speeding car opened fire into a crowd.

“All of a sudden, I hear about eight shots go off. It sounded like a strong gun, like a cannon,” witness Andrea Blea told the San Francisco Chronicle.

San Francisco police identified Javier Campos as a person of interest in the shooting. They said a car “associated with” Campos was seen in the area, and that he was already wanted on an outstanding homicide warrant in Oakland. He was also facing multiple warrants from Bay Area counties for gun charges.

With News Wire Services