OAKLAND, Calif. -- Four baseball fans were injured by bullet fragments from outside the Coliseum while attending a postgame July 4 fireworks show, Oakland police and the Athletics said Tuesday.

None of the injuries were life-threatening, police and the A's said.

Because the A's 5-1 victory over the Blue Jays lasted just 2 hours, 27 minutes, it wasn't yet dark enough for the fireworks show to start. Fans from a season-high crowd of 24,403 were allowed onto the playing field just after 9 p.m. local time.

"The Oakland Police Department [OPD] is investigating firearm-related injuries that occurred on July 4, 2022, after 9:30 p.m., in the 7000 block of Coliseum Way," police and the A's said in a joint statement.

Police initially were notified of a possible shooting victim inside the ballpark, and officers located three fans struck by bullet fragments "from what appears to be celebratory gunfire occurring throughout the city of Oakland," the statement said. An additional victim walked into a hospital.

"I think if it wasn't Fourth of July, it would be more alarming. Any time during Fourth of July, I can remember this growing up, it's never safe but people tend to do things that aren't in the ordinary," A's manager Mark Kotsay said before the series resumed Tuesday night. "That's firing weapons in the air in terms of celebration. It's really unfortunate that we had that happen here in the Coliseum and there were people injured. I know we've reached out to those people."

An investigation is ongoing, and the Oakland Police Department and Crime Stoppers of Oakland offered a reward up to $20,000 for information leading to an arrest or arrests.

Police reiterated their joint efforts with the A's and the team's security to keep everyone attending games in the venue safe.

"From a safety standpoint, I think the Coliseum is a safe environment," Kotsay said. "It's just unfortunate that on a holiday with the fireworks show that people were injured."