Four people were killed and three others were wounded in an early Saturday shooting at an illegal gambling club in New York City, police said.
The six men and one woman were shot just before 7am inside a building in the Crown Heights neighbourhood of Brooklyn.
Chief of Detectives Dermot Shea said four men were dead at the scene and the others were taken to hospitals with injuries that were not life-threatening.
The victims, who have not been identified, ranged in age from 32 to 49, Shea said at a briefing near the shooting. Two may have lived out of state and the rest were from neighbourhoods throughout Brooklyn, Shea added.
One person was injured fleeing.
No arrests have been made, and police do not know the motive for the shootings, Shea said. He said two guns were found at the scene and more could potentially be found.
Mayor Bill de Blasio said on Twitter that the city "awoke to senseless gun violence."
The Democrat added, "I've said it before and I'll say it until I can't anymore: we have an epidemic of gun violence that spares no community — and it won't stop until we get guns off our streets once and for all."
The shooting was the second mass killing in New York in a week in a city that has seen a marked drop in homicides in recent years. Four homeless men were beaten to death by another homeless man October 5 in the Chinatown neighbourhood. In 2000, there were more than 600 homicides in the city. Last year, there were fewer than 300.
A sign on the building where the bloodshed occurred says Triple A Aces. Shea said there was "evidence of gambling" including cards and dice inside.
The gambling operation was unlicensed but police had not previously received any complaints about the location, Chief of Patrol Rodney Harrison said.
Crime scene tape surrounded the building Saturday morning and investigators in white jumpsuits could be seen going in and out.
The block where the shots rang out has empty storefronts and boarded-up buildings as well as renovated townhouses.