Debris found on the Indian Ocean island of Reunion is to be transported to France to find out whether it is from the missing flight MH370, Malaysia's prime minister has said.
Initial reports suggest the 2m-long object is very likely to be from a Boeing 777, Najib Razak said.
The Malaysia Airlines flight - a Boeing 777 - vanished while travelling from Kuala Lumpur to Beijing in March 2014.
The search has focused on part of the southern Indian Ocean east of Reunion.
Oceanographer David Griffin, of Australia's national science agency, told the BBC that the location of the find was "consistent with where we think debris might have turned up".
There were 239 passengers and crew on board the plane when it went missing.
At the scene: Milton Nkosi, BBC News, Reunion
Watching the waves crash into the beach on the east coast is a stark reminder of the sheer power of the South Equatorial Current that carries tons of debris across the Indian Ocean. The search area overseen by Australian authorities is thousands of kilometres away.
Another factor fuelling speculation that this is likely to be remains of MH370 is what appear to be the remain of a suitcase found by the same man who found the debris, a gardener who works for St Andres council.
Mr Najib said French authorities would take the debris to the southern French city of Toulouse - the site of the nearest office of the French body responsible for air accident investigations (the BEA) - to verify it as quickly as possible.
He said the location of the debris was consistent with drift analysis provided to Malaysian investigators.
"As soon as we have more information or any verification we will make it public. I promise the families of those lost that whatever happens, we will not give up."
Malaysia has sent a team of investigators and other officials to Toulouse and another team of experts to Reunion - a French overseas department.
The object is expected to be flown to France on Friday, a judicial source told AFP news agency.
The BBC's Chris Bockman in Toulouse says French aviation authorities have a huge hangar facility in the city to store and study wreckage, as they did with the Air France airliner that crashed on its way from Brazil to Paris in 2009.
Aviation experts who have studied photos of the debris, found on Wednesday, say it resembles a flaperon - a moving part of the wing surface - from a Boeing 777.
BBC transport correspondent Richard Westcott says the object may have a data tag with a serial number that could be directly traceable to MH370. Even if there isn't a tag, it should have a traceable manufacturer's stamp, he adds.
The man who found the debris was named as Johnny Begue, 46, a local council worker.
"I knew immediately it was part of an aircraft but I didn't realise how important it was, that it could help to solve the mystery of what happened to the Malaysian jet," he told the Associated Press.
Mr Begue also found what appeared to be part of a damaged suitcase nearby, although it is unclear if there is a link with the aircraft part.
Location of a flaperon on a Boeing 777
A French police helicopter has been scouring waters around Reunion for other debris.
Search efforts for MH370, led by Australia, are focused on an area west of the Australian city of Perth - about 4,000km east of Reunion.
The Australian government has described the discovery of the wreckage as "a very significant development".
Simulation of where debris in search area could end up
After MH370 disappeared from radar screens, experts analysed data from faint "pings" the aircraft sent to satellites to narrow down its possible location.
More than half of those on board the plane were Chinese citizens.
A spokesperson for China's foreign ministry said: "We have noticed the reports and are wasting no time in obtaining and checking the information."
A group of relatives of many of the Chinese passengers said in a statement that they wanted "100%" certainty about where the part is from, and that the search for the airliner should continue.