President Vladimir Putin has slammed a US decision to jail Russian citizen Maria Butina for 18 months last Friday for working on behalf of a foreign government without registering.
Mr Putin said the jailing was an outrage and Butina's treatment by US authorities a travesty.
She was found guilty of trying to infiltrate the US National Rifle Association and sway activists to shift American policies in favour of Russia.
"It's not clear what she was convicted of or what crime she committed," Mr Putin said in Beijing. "I think it's a prime example of saving face. They arrested her and put the girl in jail.
“But there was nothing on her, so in order not to look totally stupid they fixed her up with an 18-month sentence to show that she was guilty of something."
Butina, 30, pleaded guilty to conspiring to act as a foreign agent. She told the court she had destroyed her life.
"I humbly request forgiveness," she told the court in Washington before her sentence was announced. "I'm not this evil person depicted in the media."
The NRA is seen as close to the Republican Party and US President Donald Trump, who has long been accused of having extensive links to Russia.
Prosecutors said that although she worked openly and was not tied to any Russian intelligence agency, she was sending back reports to a high-level Moscow official and posed a threat to the US.
Butina is said to have sent regular updates to her handler Alexander Torshin, who was then a senior Kremlin politician and central bank deputy governor who accompanied her to NRA conventions.
"The accusations brought against her, intended to influence the internal political process in the United States, are totally invented and fabricated," the Russian Foreign Ministry said.
"Our compatriot was condemned just because she is a Russian citizen."