Juneteenth celebrations were marred by 19 mass shootings that killed at least 12 people and injured more than 100 across the nation during the three-day weekend that ended Monday (June 19), CBS News reports.

The shootings were spread out across the nation, from Baltimore on the east coast to Southern California.

In Willowbrook, Ill., a suburb of Chicago, at least 23 people were shot Sunday (June 18), one of them fatally, at a Juneteenth celebration at a parking lot attended by hundreds of people, the Associated Press reported. The DuPage County Sheriff’s Office said the event was “a peaceful gathering” that suddenly turned violent when people fired multiple weapons into the crowd. Authorities did not immediately determine a motive for the shooting or make any arrests.

Also on Sunday, at least one juvenile was killed and nine other injured at a Juneteenth party in downtown St. Louis, CNN reported. Authorities said the victims ranged in age between 15 and 19 years old, and the individual who died was a 17-year-old male. Investigators recovered several guns from the scene, including an AR-15 style assault rifle, and arrested a 17-year-old suspect.

In Milwaukee, six youths were shot and wounded Monday afternoon after a Juneteenth celebration had ended. Police say four girls ranging in age from 14 to 18, a boy, 17 and a man, 19, were each struck by gunfire after a fight broke out between a group of girls. The victims were taken to a hospital for treatment of nonfatal injuries, the Milwaukee Journal-Sentinel reported.

The COVID-19 pandemic marked the beginning of a surge in gun violence across the nation. There was a 15 percent increase of firearm-related incidents between March 2020 and February 2021.

Black Americans suffer disproportionately from gun violence, experiencing 12 times the gun homicides compared to white Americans, according to research from Everytown for Gun Safety, a gun control advocacy group co-founded by former New York City Mayor Michael Bloomberg. On an average day, 34 Black Americans are killed by guns and more than 110 experience non-fatal injuries.