Australia will continue to lead the search into flight MH370 following confirmation that the wreckage washed up on an Indian Ocean island was part of a wing from the missing plane.
Prime Minister Tony Abbott confirmed the search "must go on" and said that the discovery indicated the plane had crashed close to where they had previously thought it had.
"What we have found in the West Indian Ocean does seem to indicate that the plane did come down more or less where we thought it did and it suggests for the first time we might be a little bit closer to solve this baffling mystery," Mr Abbott said. 
Malaysian Prime Minister Najib Razak confirmed on Thursday morning that a Boeing 777 wing segment discovered on Reunion Island was from MH370.
It was the first substantial breakthrough in the international search for the plane, which vanished on its way from Kuala Lumpur to Beijing 17 months ago.
Mr Najib also described the finding of the wing part as a breakthrough.
"Today, 515 days since the plane disappeared, it is with a heavy heart that I must tell you that an international team of experts have conclusively confirmed that the aircraft debris found on Reunion Island is indeed from MH370,"he said in a televised statement, at 2am Kuala Lumpur time on Thursday.
However, France stopped short of declaring it was from MH370, saying only that there was a "very strong presumption".
Mr Najib's statement suggests MH370 flew off course for hours early on   March 8 last year but it is not known if the passengers were then alive or dead. Six Australians were on board.
The comments by Malaysia Airlines and the Malaysian leader appear to reflect the opinion of experts that more debris will be found despite that winds and sea currents pushed the wing part almost 4000 kilometres from where the plane is believed to have crashed.
They also reflect confirmation that an Australian-led search is being conducted in the right area of the southern Indian Ocean.
Australia has spent more than $100 million on the mission so far.
"I believe it is appropriate because not only were there six Australians on that plane, but millions of Australians - nearly every Australian - at some point in time is an air traveller," Mr Abbott said.
Foreign Minister Julie Bishop said in Kuala Lumpur that the debris would help give a "better idea" of the length of the search but was unable to say how long it might take to find the rest of the plane.
"This is a very large inhospitable section of ocean in the southern Indian Ocean," she said. "It is a huge task ... I can't give an estimate of how long this will take."
She said the families and friends of the 239 people on board have been through what must be an "unbearable time".
"I am aware our consular team have been in touch with the Australian families," she said.
The underwater search is currently focused on a 120,000-square-kilometre area in the southern Indian Ocean.
Everything that washed up in recent days on nearby shores of eastern Africa, Madagascar and other islands in the region were now "of more interest".
Chinese relatives of passengers aboard the missing flight expressed anger and disbelief after Malaysia's Prime Minister said the wreckagewas "conclusively" from the plane. Of the 239 people on the ill-fated flight, 153 were Chinese nationals.
Lin Xiaolan, whose son Lin An'nan was on board the Malaysia Airlines flight, said she had stayed up overnight monitoring news updates.
She said the discovery of the flaperon did little to convince her that the plane had indeed ditched in the Indian Ocean, where the Australian-led search continues, adding that recent reports into the Mr Najib's personal finances had only further dented his credibility in their eyes.
"We are furious about this news," she said. "There are so many satellites in the world but they didn't know [where MH370 was] yet the rubbish collector did?