Experts hunting for dozens of Second World War Spitfires thought to have been buried in the Burmese jungle have found no planes at the sites they have been searching, sources have said.
Archaeologists have spent nearly two weeks trying to unearth unused unassembled aircraft which they believed were packed into crates and buried by the RAF in 1945.
But it is understood they failed to find any Spitfires at two sites they were looking at.
Some 36 planes were thought to be lying undiscovered in Mingaladon - one of three potential locations in the country - with as many as 124 buried in total.
Farmer and aviation enthusiast David Cundall, from Lincolnshire, who is spearheading the dig, is set to remain in Burma to investigate a neighbouring site and another potential burial area, sources said.
A press conference scheduled for Sunday to announce the findings of the dig was postponed by Wargaming Ltd, which is funding the project.
Before flying out to Burma, Mr Cundall had outlined plans to return the planes to Britain for restoration in the hope they could be flown again.
He claimed the discovery of Spitfires, if successful, would match the importance of finding Tutankhamun's tomb in Egypt.
The 21-strong excavation team has included researchers from the University of Leeds and British war veteran Stanley Coombe, from Eastbourne.
Mr Coombe, now in his early 90s, was stationed in Burma at the end of the Second World War and was one of eight eye-witnesses who claimed to have seen the Mark XIV Spitfires being buried 68 years ago.
Archaeologists have been digging close to Burma's main international airport and admitted their search would take longer than expected after a survey discovered bundles of electric cables in the way.
Soe Thein, a retired Burmese geology professor said previously that the team had found crates that could contain the planes at Rangoon airport.
Cables and water pipes were found above them and there was no blueprint for their precise locations, he said.
The dig was allowed to go ahead after a meeting between Prime Minister David Cameron and Burmese president Thein Sein earlier this year.