Multiple mass shootings occurred across the United States over the Halloween weekend.

Law enforcement will beef up its presence in a Dallas entertainment district where several deadly shootings occurred over the weekend, federal authorities announced Monday as they joined elected officials nationwide in decrying gun violence in popular public places.

Across the country, numerous mass shootings on Halloween weekend left at least 10 people dead and dozens more injured. In Dallas, three shootings in Deep Ellum, a neighborhood of music and restaurants, left four people dead and 15 injured over the span of an hour and 15 minutes early Sunday.

“Everyone deserves the freedom to walk down the street, to celebrate a fun night out during our nation’s holidays and to simply exist in public without fear for their safety or their children’s safety,” Ryan Raybould, U.S. attorney for the northern district of Texas, said at a news conference.

Many shootings occurred around gathering spots during the confluence of what might be one of the last spells of warm weather this year that drew large crowds outside on Halloween, which this year happened to fall on a weekend.

As investigators continued to look for suspects and the motives behind the shootings, word spread of even more mass violence over the weekend. Two separate shootings occurred in Birmingham, Alabama, after the annual “Magic City Classic” college football game Saturday night. And police in college towns reported shootings in their nightlife districts where annual Halloween gatherings are popular, including in Fayetteville, Arkansas; Newark, Delaware; Bloomington, Illinois; and Bloomington, Indiana.

Deep Ellum also saw deadly violence earlier this year

Dallas Police Chief Daniel Comeaux said police were pursuing leads on possible suspects in the Deep Ellum shootings, which he called “senseless” and the result of arguments. It’s undetermined if the shootings were related.

Comeaux and Raybould were joined by others at a news conference to announce “Operation Deep Cover,” a federal and local law enforcement response to gun violence in Deep Ellum.

Raybould said one man who allegedly wore a ski mask and pointed a loaded gun in the direction of a crowd in Deep Ellum was charged with being a felon in possession of a firearm.

The entertainment district experienced deadly violence earlier this year. Two people were fatally stabbed outside a nightclub in February, and a security guard was shot and killed while trying to break up a fight inside a nightclub in May. Among nonfatal shootings, five people were wounded outside of a sports bar in May, police said.