Two people were killed Tuesday when a TV news helicopter crashed to the ground on top of at least two cars near a landmark tower in Seattle, officials said.

Two people were killed Tuesday when a TV news helicopter crashed to the ground on top of at least two cars near a landmark tower in Seattle, officials said.

One other person was critically injured in the crash, which sent a huge plume of black smoke into the sky yards from the West Coast city's Space Needle, a popular tourist attraction.

"The two people that were on board that helicopter .. are both deceased. We've searched the wreckage, we have not found anybody else," said Seattle Fire Department spokesman Kyle Moore

A 37-year-old man was being treated in hospital for burns, he said.

TV pictures showed the burning wreckage strewn along a street next to a building next to the Space Needle.

"What we have left is basically just part of the tail, and burnt out metal from the main chassis of the helicopter," Moore told reporters near the scene of the accident.

An eyewitness cited by King5 television said it landed right on top of at least two cars. The unnamed eyewitness said he saw a badly-burned person escape from one of the vehicles.

There was no immediate word on what caused the crash.

News reports said the chopper belonged to KOMO, a local television station. King5 television said it shared use of the helicopter involved with KOMO, to cover news in the city.

The fire department spokesman said that initial calls suggested the chopper could have hit the Space Needle itself, or a nearby building.

"We were getting multiple reports that it might have hit a building .. one of the original callers said they thought it hit the Space Needle," he said.

But he added: "We have no indication that the helicopter hit a building. I don't know what caused it to crash into the ground."

The area around the crash would remain sealed off until at least Wednesday for air accident investigators to search the scene, he added.