Describing her treatment a travesty of justice the Russian president said the sentence looked like an attempt by US law enforcement and judicial officials to save face.
An admitted agent, Butina was sentenced by a US District Court judge in Washington DC where she expressed remorse for conspiring with a Russian official to infiltrate a gun rights group and influence American conservatives.
In his first comments about the case since the sentencing, Mr Putin told reporters in Beijing: “It’s an outrage. It’s not clear what she was convicted of or what crime she committed. 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 gave her, fixed her up, with an 18-month sentence to show that she was guilty of something.”
Butina admitted to conspiring with a Russian official and two Americans from 2015 until her arrest to infiltrate the National Rifle Association (NRA).
Prosecutors said that while she did not engage in “traditional” spy craft, she worked behind the scenes to make inroads in conservative political circles and promote friendlier US- Russian ties.
She arranged dinners in Washington and New York and attended events to meet high-profile politicians.
Until Friday, Butina had not made any significant public comments since her arrest, but her remarks in court contradicted the Kremlin’s account that she had been forced by the US to falsely confess to the “ridiculous” charge of being a Russian agent.
“I destroyed my own life,” Butina told the judge. “While I know I am not this evil person who has been depicted in the media, I am responsible for these consequences. Now I beg for mercy, for the chance to go home and restart my life.”
Her lawyers argued her crime was down to a simple failure to notify the Justice Department of her activities on Russia’s behalf.
“If I had known to register as a foreign agent, I would have done so without delay,” Butina told the judge. “I just didn’t register because I didn’t know to.”
Judge Tanya Chutkan imposed a sentence that matched the prison term prosecutors requested and also agreed to have Butina deported back to Russia after she completes her incarceration.
The sentence included the nine months she already has served in jail since her July arrest, meaning she will serve another nine months in prison.
Mr Putin also said Moscow was considering offering all Ukrainian citizens fast-tracked Russian passports. The move will likely anger some politicians in Ukraine which has been at war with pro-Russian separatists since 2014.
He made the statement days after signing an order to simplify the procedure for obtaining a Russian passport for residents of separatist-controlled eastern Ukraine.
The Russian president also said he wanted to know the position of Ukrainian President-elect Volodymyr Zelenskiy on the conflict in eastern Ukraine following the comedian's election victory.
“If we have a meeting sometime, begin some negotiations, which I do not rule out, then we will first of all have to talk about how to end the conflict in the southeast of Ukraine.”
Additional reporting by agencies