A minor, 3.6-magnitude earthquake struck in the San Francisco Bay Area on Sunday, according to the United States Geological Survey.

The temblor happened at 8:37 a.m. Pacific time about 1 mile southwest of Alamo, Calif., data from the agency shows.

As seismologists review available data, they may revise the earthquake’s reported magnitude. Additional information collected about the earthquake may also prompt U.S.G.S. scientists to update the shake-severity map.

Aftershocks can occur days, weeks or even years after the first earthquake. These events can be of equal or larger magnitude to the initial earthquake, and they can continue to affect already damaged locations.

Police still had no suspects in custody Sunday after a weekend shooting near an Ohio street festival wounded 12 people and sent attendees scrambling for cover in a busy Toledo neighborhood.

Toledo Deputy Police Chief Joe Heffernan said it appeared that at least two people fired weapons on Saturday near the Old West End Festival and were “probably shooting at each other.”

Authorities say a search for the the shooters was ongoing and had not identified any potential suspects. They urged festivalgoers to come forward with any photos or videos.

“As far as violence, this is over the top, right?” Toledo police Lt. Dan Gerken said. “Twelve people being shot, that’s the most I’ve been to a scene. I’ve been to a lot of scenes, but this is way over the top.”

Hundreds of people were at the festival, an annual two-day celebration in Toledo’s historic district that includes live music, food vendors, home tours and shopping.

The remainder of the festival was canceled Sunday. Organizers said “it would not be compassionate, responsible or possible to continue.”

“We are heartbroken about those that were injured at the Old West End Festival,” the festival said in a statement.

Two of the victims were in critical condition on Saturday, Heffernan said. The ages of the victims ranged from 14 to 61, with most of them in their early 20s.

Multiple videos posted to social media showed people running amid the sound of gunshots and emergency officials tending to others who appeared wounded.

Fire Chief Allison Armstrong said it was difficult to get to the hospital due to closed roads and traffic from people leaving the festival, but emergency responders were able to transport all patients from the scene within an hour.

Kevin Berry was sitting in the neighborhood arboretum listening to live music with friends when he heard a handful of gunshots ring out.

“Everybody hit the deck,” he said.

When Berry looked back up, he saw a gun being tossed to the ground less than 50 feet (15 meters) away from him. Officers who were already on site for the festival responded immediately.

Berry, who has medical training and served in the Navy, walked around looking for anyone who might need help and saw at least five people with gunshot wounds.

“The folks who were hit were spread out around the arboretum area,” he said.

George Kral, the city’s safety director, said the Old West End Festival is one of the most iconic festivals in Toledo.

“And it’s a shame that something like this had to ruin it,” Kral said.

A shooting near a community festival in Toledo, Ohio, wounded at least 12 people on Saturday, with police saying a search for the suspects was ongoing.

Two of the wounded were in a critical condition, Toledo deputy police chief Joe Heffernan said. He said it appeared there were at least two people firing weapons who were “probably shooting at each other”.

The Toledo police department said the shooting happened near the Old West End festival, an annual gathering of live music and home tours in a historic district of the city.

The department said an active search was under way for those responsible.

“I am deeply concerned about the situation in Toledo tonight,” Ohio governor Mike DeWine said in a statement. “Summer festivals should be safe spaces for families to spend time together without fear of violence.”

Multiple videos posted to social media showed people running over the sound of gunshots and emergency officials tending to others who appeared wounded.

Kevin Berry said he was sitting in the neighbourhood arboretum listening to live music with his friends when he heard a handful of gunshots ring out.

“Everybody hit the deck,” he said.

When he looked back up, he saw a gun being tossed to the ground. Police officers who were already on-site for the festival immediately responded to the scene.

Berry, who has medical training and served in the US Navy, said he walked around the area looking for potential victims who might need help.

He said he saw at least five people with gunshot wounds.

“The folks who were hit were spread out around the arboretum area,” he said.

The Old West End festival is a two-day celebration in Toledo’s historic district that includes live music, food vendors, home tours and shopping.

“This tragedy is really weighing heavily on both the residents and those who visit and enjoy this festival year after year,” said city council member Theresa Morris.