A heartbreaking scene unfolded in Los Angeles after an NBC news helicopter crashed while a reporter from the network was covering a separate incident nearby.

NBC 4 journalist Robert Kovacik was reporting on a bus crash in the Chatsworth area on Tuesday evening, September 15, when a helicopter suddenly fell from the sky and crashed into a parking lot at around 7pm local time.

At first, Kovacik did not know what aircraft had gone down or whether it was connected to his own network.

As smoke could be seen rising from the area, the reporter was told by firefighters to move away from the scene while emergency crews responded.

"We don't know where the chopper is from, we don't know if it even is a chopper, if it's a news chopper, we are just looking right now," Kovacik said during the unfolding coverage.

But as further information emerged, the devastating reality began to sink in.

Kovacik realised that the helicopter could be carrying members of his own news crew.

"Dude that's my crew in there, that is my own crew," he told a police officer, according to reports.

"We are gonna get them evacuated, this isn't safe," the officer responded.

It was later confirmed that the aircraft was News Chopper 4, operated by NBC 4 and its Spanish-language sister station, Telemundo 52.

Three people died in the crash. They were identified as NBC 4 photojournalist Eliana Moreno, pilot George Marciniw and an unnamed civilian.

Two other people were taken to hospital following the crash. Their conditions have not been publicly confirmed.

The tragedy was also confirmed live on NBC by host Colleen Williams, who was presenting coverage as the network learned that its own helicopter had been involved.

"We can now confirm that the chopper that went down in Chatsworth tonight, about two hours ago, was in fact news chopper four," Williams said.

She explained that the newsroom had been trying to piece together what had happened after losing contact with the crew.

NBC Los Angeles and Telemundo 52 later released a joint statement expressing their grief over the fatal accident.

"We are deeply saddened to share that a helicopter providing aerial news coverage for NBC4 and Telemundo 52 was involved in a fatal accident in Los Angeles on Tuesday evening," the stations said.

"We extend our heartfelt condolences to the families, friends and colleagues of those who lost their lives."

Speaking on NBC's Today show the following morning, NBC Los Angeles anchor Lynette Romero described the network's employees as heartbroken following the deaths of Moreno and Marciniw.

Romero said both journalists had been doing work they loved and spoke about their passion for breaking news and working aboard News Chopper 4.

The National Transportation Safety Board is now investigating the crash to determine what caused the helicopter to fall from the sky.

The incident has left colleagues and viewers mourning the loss of two members of the NBC news team, with the investigation expected to establish more details about the circumstances surrounding the fatal accident.