NEW YORK >> A fire at a New York City e-bike shop quickly spread to upper-floor apartments and killed four people early today in the latest deadly blaze linked to exploding lithium-ion batteries.

The fire, reported shortly after midnight, happened at a shop that was cited last summer for safety violations related to the storage and charging of batteries, officials said.

A pile of burned bikes, scooters and other debris lay on the sidewalk outside the shop, HQ E-Bike Repair, which was on the ground floor of a six-story building in Manhattan’s Chinatown neighborhood.

So far this year, there have been more than 100 fires and 13 deaths linked to battery explosions in the city, said Fire Commissioner Laura Kavanagh.

“There was a very large number of both batteries and e-bikes,” Kavanagh said at a morning news conference. “This location is known to the fire department. We have written violations at this location before and we have conducted enforcement at this location before.”

Two men and two women died in today’s fire. Two other women were hospitalized in critical condition, officials said. A firefighter suffered minor injuries.

Kavanagh said it was “very clear” that the fire was caused by lithium-ion batteries, which can overheat while being charged and explode in an intensely hot flare of flame, but that the exact cause was still under investigation.

Chief Fire Marshal Daniel Flynn said the shop was inspected last August and later cited for safety violations related to battery charging, the number of batteries at the site and the electrical system. The shop was fined $1,600. Authorities recently surveilled the store and found there were many batteries there, but none of them were being charged at the time, he said.

A man who said he was the owner of the bike shop told The Associated Press that he made his usual checks of the store before he left Monday night. He denied that any e-bike batteries were being charged.

“The shop has been there for six years. I check before I leave every night,” said the man, who spoke in Mandarin in a phone interview and only gave his last name, Liu. “I checked last night, turned off the power besides the ones for the monitor and automatic door.”

He added: “I got a call from a neighbor … and told me about the fire. I went to my shop but couldn’t get close when they were working on the fire. I saw a lot of smoke. My shop is gone. I’ve been working for nothing for years.”

Liu said he was at the police station waiting to talk with officers this morning.

The blaze startled the neighborhood in the middle of the night.

“A friend of mine came in and yelled ‘there’s a fire next door,’” neighborhood resident Belal Alayah told WABC-TV. “I step out. I see the flames so hot it’s going through the metal gate. I knew it was the bike store, so I called the fire department. But the fire kept getting bigger and bigger and it took them a while to stop the fire.”

Electric bikes have become popular, non-gasoline-powered ways to make deliveries, commute and zip around a city that has promoted cycling in recent decades. Many run on lithium-ion batteries, which have been blamed for numerous fires.

In April in the Queens section of New York City, two children were killed in a fire blamed on an e-bike. Another Manhattan fire in November that injured more than three dozen people was caused by a malfunctioning e-bike battery, officials said.

Last year in the city, nearly 200 fires and six deaths were tied to such batteries, with an 8-year-old girl and a 5-year-old girl among those who died in blazes linked to scooter batteries. Fire officials have repeatedly issued warnings and safety tips, and the city passed new regulations this year aimed at preventing battery fires.

“So we would like to really emphasize today something that we have been saying over and over … it is also very, very important to get the word out how incredibly dangerous this is,” Kavanagh said. “This exact scenario where there’s an e-bike store on the first floor and residences above and the volume of fire created by these lithium-ion batteries is incredibly deadly.”

Lithium-ion batteries can catch fire because they contain a flammable electrolyte solution that allows electrical current to flow, experts say. Many fires have been linked to such batteries in laptops, cellphones and other items.