Four people were killed in separate shootings across New York City late Saturday and early Sunday, the police said.

The killings were a reminder of the pockets of violence that exist in the city, even as it has become safer in recent years. Two of the shootings, in the Bronx and in East New York, Brooklyn, happened in police precincts that are among the city’s deadliest.

No arrests had been made in any of the killings as of Sunday evening.

The first shooting was reported shortly after 9:30 p.m. Saturday, near the intersection of East 175th Street and Monroe Avenue in the Mount Hope section of the Bronx, the police said. A man, identified by the police as Marvin Harris, was shot three times in the abdomen, and in an arm and a leg.

Mr. Harris, 32, was taken to Bronx-Lebanon Hospital Center, where he was pronounced dead, the police said.