An FDNY emergency medical technician and mother of five was killed and her partner was injured in the Bronx Thursday when a man stole their ambulance and ran over one of the first responders, officials said.

EMT Yadira Arroyo, 44, a 14-year veteran of the FDNY, died at Jacobi Medical Center, where her partner, EMT Monique Williams, 31, was treated for minor injuries, sources said.

“They were acting very bravely, they certainly wanted to continue on their way to the call,” FDNY Commissioner Daniel Nigro said after meeting with Williams and Arroyo’s families at Jacobi.

The nightmare unfolded in Soundview around 7:10 p.m. when the pair realized that a man was riding on the back bumper of their ambulance as they responded to a call about a pregnant woman, officials said.

Witness Anis Nagi, 40, said he and others flagged down the ambulance when they saw the man riding on the back.

The deranged joyrider — identified by NYPD as Jose Gonzalez — jumped off and tried to steal a backpack from a 21-year-old, sources said. The medics pulled over and tried to help.

“The female EMT came out of the vehicle,” Nagi said. “She left the door open.”

The 25-year-old Gonzalez started to walk away, but then turned back and went around Arroyo to the cab of the ambulance and got into the driver’s seat, officials said.

“This person had no business being in this ambulance,” Nigro said.

As the emergency medical workers struggled with the man on both sides, the vehicle throttled backward — knocking Arroyo down.

“He reversed so hard and she was dragged,” Nagi said. “He ran over her and she went under the wheels.”

Video of the horror shows the ambulance backing up into a green taxi before lurching forward, the driver’s side door ajar, and cutting across traffic.

Arroyo can be seen being dragged beneath the wheels of the massive vehicle for at least 15 feet.

The ambulance then turned onto Watson Ave., slammed onto the sidewalk and hit a parked car, officials said. The EMT’s motionless body was left in the middle of the street.

A second video shows the stunning aftermath of the carnage.

Gonzalez, who sources say has a lengthy criminal record, was tackled by passing MTA Officer Daniel McCabe and a group of good Samaritans, police said. “He was incoherent and talking to himself,” a source said.

Williams wailed in horror over her partner’s body before being restrained by cops as she tried to kick the man who killed her colleague.

Nancy Montavo, an office manager, said the screams will haunt her. “She was screaming, ‘my partner, my partner!’ She was screaming hysterically. I can’t forget her screaming,” Montavo said. “All the police came running and they put her in an ambulance.”

Mayor de Blasio rushed to Jacobi Medical Center Thursday night.

De Blasio said Arroyo was “lost in the line of duty, bravely doing her job, encountering the kind of danger our EMTs should not have to confront.”

Arroyo, who was assigned to Station 26 in Morrisania, is the eighth member of EMS killed in the line of duty, officials said.

Gov. Cuomo tweeted, “EMTs are heroes who help countless New Yorkers every day. Tonight’s tragedy in the Bronx is horrible. My deepest sympathies to the family.”

Gonzalez was arrested and faces murder, grand larceny and DWI charges.