“We’re praying for the swift recovery of the five people — including two children — struck by gunfire in the Bronx tonight,” Mayor Bill de Blasio said on Twitter.

Adam Lin, the manager of Courtlandt Wine & Liquor, on Courtlandt Avenue near 151st Street, said he had heard gunfire in the area before, but he thought the noise he heard just before 4 p.m. on Wednesday was from a construction project nearby.

“I wasn’t sure until I saw the crowd in the street and people ran into my store,” Mr. Lin said, standing in the store’s doorway shortly after 7:30 p.m. Behind him, a worker wearing disposable blue gloves mopped blood off the floor.

Mr. Lin said that about a half-dozen people rushed into the store after he heard the gunfire and that a woman in the group told him three of them, including “a little boy,” had been hit. They were screaming and “seemed scared,” Mr. Lin said. Someone in the group called out, “He’s my brother,” he added.

Mr. Lin said the police had arrived as he was calling 911.

William Polson, who works at a deli up the block, said he saw three people, including a boy, taken out of the liquor store on stretchers. Mr. Polson said that an ambulance took a fourth person, a man who had been lying on the curb, away.