When bullets go up, they must come down. 

That was the stark reminder Monday from Philadelphia's law enforcement officials, who are urging residents not to shoot guns into the air to celebrate New Year's Eve.

District Attorney Seth Williams says that anyone caught firing shots will be charged with reckless endangerment, or a more serious crime if warranted.

"We want to remind everyone that there is zero tolerance in Philadelphia for people shooting firearms in the air to celebrate the holiday," he says. "It's a stupid act that can have deadly consequences."

Last New Year's Eve, Philadelphia police received 154 reports of gunfire over the course of four hours. On an average night, police get about 10 reports in the same time period.