Former US marine Paul Whelan, who is accused of spying by Russia, must remain in custody while he awaits trial, a court in Moscow has ruled.
Russian security officials say that he was “caught spying” last month.
Mr Whelan, 48, who also holds British, Canadian and Irish nationality, was found with a memory stick containing state secrets, his lawyer said.
He had not opened the “thumb drive” and had been expecting holiday pictures and videos, the lawyer added.
“Paul was actually meant to receive information from an individual that was not classified. These were cultural things, trip to a cathedral, Paul’s holiday,” said Vladimir Zherebenkov.
“He could not see (the contents) because he was arrested.”
Mr Whelan insists that he is innocent and his family have told the BBC that he was simply visiting Russia to attend a wedding.
He appeared in court in Moscow on Tuesday to appeal against a decision to deny him bail. He is awaiting trial on espionage charges and, if found guilty, could face up to 20 years in jail.
Few details of the case against him have been made public, but his lawyer told the BBC that Mr Whelan was in good spirits and is determined to prove his innocence.
Mr Zherebenkov added that he had seen no evidence from investigators that showed his client was a spy.
“I saw him last week… he feels well, he has a sense of dignity,” he told reporters outside the court on Tuesday.
A spokeswoman for the US embassy in Moscow told Russian media it was “closely following” the case and called for a “fair and transparent trial”.
What was Paul Whelan doing in Russia?
Mr Whelan arrived in Russia on 22 December to attend a wedding and had planned to visit Russia’s second city, St Petersburg, in addition to Moscow before flying home on 6 January, his brother told the BBC.
He was arrested on 28 December, having taken a group of wedding guests on a tour of the Kremlin museums in the morning. He was last heard from in the early evening and failed to show up for the wedding, David Whelan said.
Russia’s FSB state security agency has given few details, saying only that he was detained “during an act of espionage”, a wording that implies he was caught red-handed, the BBC’s Sarah Rainsford reports.
His family say he has been visiting Russia for business and pleasure since 2006.
Who is Paul Whelan?
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.
He is a citizen of four countries – the US, the UK, Canada, and the Irish Republic.
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 have not been made public.