A New Zealander has told authorities he saw Malaysia Airlines flight MH370 "burning at a high altitude".
ABC reporter Bob Woodruff tweeted an image of an email from Michael McKay, who is working on an oil rig in the South China Sea, to his employer describing what he saw.
Mr McKay started the email by saying that he believes he saw the Malaysia Airlines plane go down, saying that the "timing is right".
He says he saw the plane "burning at a high altitude" while he was aboard the oil rig "Songa Mercur" off Vung Tau.
"While I observed the burning (plane) it appeared to be in ONE piece," he wrote, saying that it was about 50-70 kilometres from his location.
He also revealed the "surface location of the observation is: Lat 08" 22' 30.23" N; Long 108" 42' 22.26" E".
"From when I first saw the burning (plane) until the flames went out (still at high altitude) was 10-15 seconds," he wrote.
"There was no lateral movement, so it was either coming toward our location, stationary (falling), or going away from our location."
McKay's employer at the oil rig in the South China Sea has confirmed the letter is not a hoax.
Mr McKay said in the email he had tried to contact Malaysian and Vietnam officials but was not sure if they had received his message.
Doan Huu Gia, deputy general director of Vietnam's air traffic management, told BBC: "We received an email from a New Zealander who works on one of the oil rigs off Vung Tau.
"He said he spotted a burning [object] at that location, some 300 km southeast of Vung Tau."
Woodruff reports that Vietnamese officials say they found nothing at the site.