Malaysian Prime Minster Najib Razak confirmed last night that Malaysia Airlines Flight MH370, with 239 passengers and crew, plunged into the southern Indian Ocean with no survivors.
In a sombre and emotion-charged announcement, Mr Razak said that Immarsat, the British-based satellite company working with the UK Air Accidents Investigation Branch, had used new analysis techniques and determined "beyond doubt" that MH370 had been lost and no one had survived.
"Therefore, it is with deep sadness and regret that, according to new data, MH370 ended its flight in the southern Indian Ocean," he said.
Relatives of passengers and crew had been told of the "heartbreaking" news.
He said he would reveal more details this morning.
In a day of high drama yesterday, two new debris fields were spotted by Australian and Chinese search planes between 2100km and 2500km south-west of Perth in a zone identified by the Australian Maritime Safety Authority based on US and British intelligence.
The debris is expected to be confirmed today as coming from MH370, which disappeared 18 days ago on a routine flight from Kuala Lumpur to Beijing.
Prime Minister Tony Abbott told Parliament last night that HMAS Success was in the process of recovering two objects spotted by an RAAF Orion at 11.45am.
It remained in the area overnight.
The crew aboard the Orion reported seeing a "grey or green circular object" and an "orange rectangular object", Mr Abbott said after emerging from a Cabinet meeting. There were reports of other, smaller objects.
Mr Abbott said the objects identified by the RAAF Orion were separate to the objects reported by the Chinese Ilyushin IL-76.
A US Navy P-8A Poseidon aircraft attempted to locate the objects reported by the Chinese plane but were unable to do so.
The P-8A, a second RAAF P3 Orion and a Japanese P3 Orion continued to search last night until about 8pm.
The Chinese icebreaker Xue Long is racing to the area where spotters aboard the Chinese IL-76 sighted what they termed "significant suspicious objects".
A Xinhua correspondent aboard the Ilyushin aircraft reported that searchers saw "two relatively big floating objects with many white smaller ones scattered within a radius of several kilometres".
The Ilyushin was returning to Perth and was at an altitude of 36,000 feet when the debris was spotted.
It did not have enough fuel to descend for a closer look and returned to Perth.
Two Chinese IL-76s joined the search yesterday and departed Perth Airport at 8.45am and 9.20am as Rescue 801 and 802.
They returned mid-afternoon.
The sighting is 2174km south-west of Perth and in the general area of the Chinese satellite image taken four days ago.
AMSA yesterday launched 10 aircraft to search for MH370.
As well as the two Chinese IL-76s, there were two RAAF P3 Orions, three ultra-long range civil jets, the US Navy P-8A Poseidon and two Japanese P3 Orions.
AMSA is yet to release details of the new French find, which shows "radar echoes taken by a satellite" that it termed "floating debris".
Malaysian officials said the French data consisted of radar echoes captured last Friday and converted into fuzzy images.
The objects were about 930km north of where the objects in the satellite images released by Australia and China were located.
One of the objects located by the French was about the same size as the one captured on the Chinese satellite - about 22m by 13m.