Missing Malaysia Airlines flight MH370 went down over the southern Indian Ocean, Malaysian Prime Minister Najib Razak said Monday, citing new analysis of satellite data showing the plane’s last position.

It’s believed that no one survived the crash.

Never-before-used analysis of satellite images showed that the Boeing 777’s last position was in the middle of the Indian Ocean, west of Perth, Australia, Najib said.

“This is a remote location, far from any possible landing sites,” he told a news conference.

“It is therefore, with deep sadness and regret, that I must inform you that according to this new data, flight MH370 ended in the southern Indian Ocean,” he said.

The families of the 239 passengers and crew on board have been informed of the latest finding. 

In a text message to family members, the airline said it has to assume “beyond any reasonable doubt” that none of the passengers or crew survived.

Najib said further details will be unveiled at a news conference Tuesday.

Flight MH370 was en route to Beijing from Kuala Lumpur when it vanished from the radar on March 8.

Search crews initially scoured the Gulf of Thailand and the South China Sea in hopes of finding the wreckage. But when investigators began looking into the possibility that the plane had gone off-course and headed either north or south over the Indian Ocean, the search widened.

On Monday, Australian and Chinese planes spotted floating objects in the southern Indian Ocean. An Australian navy supply ship is heading to the area to get a closer look.

Najib said Monday that the latest satellite analysis came from Inmarsat, a U.K. company that has been performing “further calculations” on the collected data.

Based on a “type of analysis never before used in an investigation of this sort,” the company and the U.K. Air Accidents Investigation Branch concluded that the plane flew along the southern corridor of the Indian Ocean and crashed, Najib said.

But one U.S. aviation expert says that without physical evidence, there is no “definitive proof” of a crash.

Keith Wolzinger, a former Boeing 777 pilot, said the conclusion that the plane crashed in the Indian Ocean “seems to be based solely” on the new analysis of satellite data.

“Without any physical evidence and without locating the flight data voice recorders, there is no definitive proof as of this moment,” he told CTV News Channel.

Wolzinger said other evidence had already been pointing investigators in the direction of the Indian Ocean “for the last seven to 10 days.”

“What this has done is narrowed the focus and will allow the search teams to focus their recovery efforts in an area that’s more definitive now,” he said.

Since it has now been established that the plane flew for a “significant period of time” after its last contact with ground control, Wolzinger said he would rule out mechanical failure or fire on board as potential causes of the crash.

He said that leaves investigators with one of three “human intervention” possibilities.

Wolzinger said those possibilities include the crew acting on their own, or “under duress” of a third party. There is also the possibility that someone commandeered the aircraft, he said.

The majority of flight MH370’s passengers were Chinese citizens. Two Canadian citizens were also on board.