In a “mass shooting incident” that occurred overnight at an apartment building in the city of Baltimore, Maryland, police reported on Sunday that two people had died and three others were in critical condition.

30 people were shot in the event in Baltimore’s 800 block of Gretna Avenue, according to the city’s police department.

An 18-year-old female was pronounced dead at the scene and a 20-year-old male was pronounced dead after being taken to a local hospital, the police said.

Three others were in a critical condition after nine people were transported from the scene to local hospitals, while 20 others affected walked into hospitals in the area, police said.

The police department said that at about 12:35 a.m. on Sunday officers responded to calls of a reported shooting at 800 block of Gretna Court.

Hundreds of people were gathered in the area for an event called “Brooklyn Day,” a witness told TV station Fox 45, adding that they had heard 20 to 30 shots fired.