Former US marine Paul Whelan, accused in Russia of espionage, has said he is not a spy and that he was set up by a Russian friend.
Speaking to the BBC, Mr Whelan, who is also a citizen of the UK, Canada and Ireland, said a friend had planted a hard drive on him without his knowledge.
The 48-year-old’s appeal against detention was denied by a Moscow court.
Prosecutors say he was caught “red-handed” with state secrets last year.
The investigation has now ended, and Mr Whelan’s lawyers have begun studying the evidence.
Because it is an espionage case, all the information is classified.
The US ambassador in Moscow has called on Russia to stop “playing games” with the case.
What did Paul Whelan say?
In a snatched conversation through the glass of his cage in court, Mr Whelan gave his side of the story for the first time, BBC Moscow correspondent Sarah Rainsford reports.
He said he had been set up, and had not committed any crime.
“A person turned up at my [hotel] room and put something in my pocket, then I was arrested,” Mr Whelan said.
“That person was an FSB [Russia’s Federal Security Service] officer. Someone I had known for 10 years. There was absolutely no reason that person should have been in the room. No reason they should have given me any sort of flash drive.”
Asked by the BBC whether there were state secrets on the drive, as the prosecution maintains, Mr Whelan said he had “no idea”.
“I never looked at it. I didn’t know I had it until I was arrested. This is 100% a provocation, and a really bad one,” he said.
Defence lawyer Vladimir Zherebenkov also described the case as “provocation”, adding that he has seen no proof so far of his client’s guilt.
Mr Whelan’s frustration, meanwhile, is clearly increasing, our correspondent adds.
When the judge returned to read his verdict – that he should be kept in custody, ahead of trial – Mr Whelan raised his voice to denounce the case as “garbage”.
Mr Whelan, who said he had been assaulted by a doctor and refused medical treatment, also called on all four governments – whose passport he holds – for their help.
Why was he arrested?
Mr Whelan arrived in Russia on 22 December to attend a wedding and had planned to visit St Petersburg in addition to Moscow before flying home on 6 January, his brother told the BBC.
He was arrested in Moscow on 28 December after taking a group of wedding guests on a tour of the Kremlin museums.
The FSB said he was detained “during an act of espionage”.
Mr Whelan’s Russian lawyer said the arrest was made after he was unwittingly handed a memory stick containing state secrets.
Who is he?
Mr Whelan was born in Canada to British parents but moved to the US as a child. He is currently director of global security for Michigan-based automotive components supplier BorgWarner.
His brother said Mr Whelan had been visiting Russia for business and pleasure since 2007.
Mr Whelan joined the Marine Reserves in 1994 and rose to the rank of staff sergeant in 2004. He served in Iraq for several months in 2004 and 2006.
He was convicted in a 2008 court martial on charges related to larceny and received a bad-conduct discharge. Details of the charges are not public.