Philadelphia police are looking for four men who robbed a jewelry store inside a mall Saturday night and pepper-sprayed employees, causing the mall to be evacuated, police said.

The men entered the Javier the Jeweler store just before 7:30 p.m. at the Philadelphia Mills Mall in Philadelphia and took various pieces of jewelry, The Associated Press reported.

Police said the men sprayed employees with a “highly concentrated OC spray” as they broke the jewelry displays with a sledgehammer, the Philadelphia Police Department said in a statement to USA TODAY. 

Police said the mall was evacuated and first responders helped treat the employees. There weren't any customers inside the store during the robbery, police said.

Police, who are still investigating, said they don’t know how much jewelry was taken.

Watch:Video shows more than 30 people steal $300,000 worth of items at Nordstrom in Los Angeles

Latest group robbery this month

The burglary is the latest robbery by a group at a shopping center this month.

On Aug. 12, California police said more than 30 people stole over $300,000 worth of items from a Los Angeles mall.

The group of people entered a Nordstrom store at the Westfield Topanga Shopping Center in Los Angeles and stole high-end handbags, clothing and “other easily re-sellable items," the Los Angeles Police Department said in a statement on social media.

On Aug. 8, at least 30 people "flooded" the Yves Saint Laurent store at The Americana at Brand in Glendale and stole about $300,000 worth of clothing and other merchandise before fleeing on foot and leaving the location in numerous vehicles, Glendale Police said in a news release.

Contributing: The Associated Press