Dozens of people were injured in a fire at a residential building in New York City on Saturday morning, authorities said.

The three-alarm fire broke out on the 20th floor of a midtown Manhattan high-rise, with a "heavy fire condition," according to the New York City Fire Department.

Thirty-eight people were transported to the hospital due to the fire, including two critically due to smoke inhalation, officials said. Five were in serious condition and the rest were minor injuries, according to FDNY Commissioner Laura Kavanagh.

Five members of the FDNY are among the patients, officials said.

"There's likely to be an increase in the number of patients as more and more families come down and are evaluated by EMS," EMS Academy Chief Joseph Pataky told reporters.

The fire was reported around 10:30 a.m. and was under control within an hour, the FDNY said.

Bystander footage captured a dramatic rescue, as a firefighter rappelled with a woman down to a floor below and went safely inside the building while smoke billowed out of windows above.

"Fire EMS and dispatch did an extraordinary job rescuing a number of civilians," Kavanagh said during a press briefing, referencing that rescue in particular. "I cannot emphasize enough the extraordinary work of our members this morning in unbelievably dangerous conditions."

Two people were rescued from the apartment where the fire originated via life-saving rope, according to FDNY Deputy Assistant Chief Frank Leeb.

The cause of the fire was determined to be a lithium-ion battery "connected to a micro-mobility device," Kavanagh said.

"The lithium-ion battery adds a different degree when we talk about the fire dynamics of it," Leeb said. "These rooms flash over in just a mere matter of seconds."

There have been nearly 200 fires so far this year in NYC caused by lithium-ion batteries for a micro-mobility device, such as an electric bike or scooter, according to Chief Fire Marshal Dan Flynn.

Authorities believe an occupant was repairing electric bikes and the fire originated directly behind the front door, he said. FDNY has recovered at least five bikes from the apartment, he said.

Kavanagh emphasized the "rising cause of fires" from e-bikes and urged people to follow the "safest possible way to use these," including not charging them overnight when they are asleep and making sure they are certified and the batteries are not damaged.

In August, a fire in a Harlem apartment sparked by a lithium-ion battery from an e-bike or scooter killed two people, including a 5-year-old girl.