An American adventurer says that when he discovered part of an aircraft on a sandbar he initially thought it was from a small plane, and not from a Malaysia Airlines flight that disappeared two years ago with 239 people aboard.
Blaine Gibson has described how a boat operator took him to a sandbar named Paluma off the coast of Mozambique and then called him over after seeing a piece of debris with "NO STEP" written on it.
"It was so light," said Gibson, who has told reporters that he has spent a long time searching for evidence of missing Flight MH370.
Photos of the debris appear to show the fixed leading edge of the right-hand tail section of a Boeing 777, said a US official, who spoke on condition of anonymity because he wasn't authorised to speak publicly. Flight 370 is the only known missing 777.
Gibson said the discovery happened after he decided to go "somewhere exposed to the ocean" on the last day of a trip to the Mozambican coastal town of Vilankulo.
"At first, all I found were usual beach detritus - flip flops, cigarette lighters. Then 'Junior' called me over," said Gibson, using the nickname of the boat operator. After being interviewed, Gibson went to the Maputo airport to take a flight to Malaysia to participate in second anniversary commemorations of the disappearance.
"It's important to keep it in perspective," Gibson said of his find. "This is about the families of the 239 victims, who haven't seen their relatives for two years now."
Gibson, who is from Seattle, said the piece of debris is now in the hands of civil aviation authorities in Mozambique, and that he expects it to be transferred to their Australian counterparts.
The location of the debris matches investigators' theories about where wreckage from the plane would have ended up, according to Australian officials.
The plane disappeared on March 8, 2014 and is believed to have crashed somewhere in a remote stretch of the southern Indian Ocean, far off Australia's west coast and about 6000 kilometres east of Mozambique.
Australian Transport Minister Darren Chester said on Thursday the location of the debris in Mozambique matches investigators' drift modelling and would therefore confirm that search crews are looking in the right part of the Indian Ocean for the main underwater wreckage.
People who have handled the part, called a horizontal stabiliser, say it appears to be made of fibreglass composite on the outside, with aluminum honeycombing on the inside, the US official said.
The Australian Transport Safety Bureau, which is running the search for the plane in remote waters off Australia's west coast, said the part is expected to be transported to Australia for examination.
Some have expressed scepticism that the part could be from the missing aircraft because it appears to be remarkably clean and free of sea life - unlike the barnacle-encrusted wing part that washed ashore on the French island of Reunion last year. That part, known as a flaperon, remains the only confirmed trace of Flight 370.