Russian national Maria Butina, who was jailed in the United States in April after admitting to working as a Russian agent, arrived in Moscow on Saturday, greeted by her father and Russian journalists who handed her flowers.
"Russians never surrender," an emotional Butina told reporters at Moscow's Sheremetyevo airport, flanked by her father and the Russian Foreign Ministry's spokeswoman.
Clutching a bouquet of white roses, the 30-year-old graduate student thanked her supporters and added she was happy to be back.
Butina pleaded guilty in December last year to one count of conspiring to act as a foreign agent for Russia by infiltrating a gun rights group and influencing U.S. conservative activists and Republicans.
Her case further strained U.S.-Russian relations, prompting Moscow to accuse Washington of forcing Butina to confess to what it described as ridiculous charges.
Earlier this year Russian President Vladimir Putin called the United States' treatment of Butina a travesty of justice and said her sentence looked like an attempt by U.S. law enforcement and judicial officials to save face.
Despite his criticism of the way Butina was treated, Putin has no plans to meet with her, Kremlin spokesman Dmitry Peskov said this week.
In the past Putin has warmly welcomed home Russian agents arrested abroad.
The Russian leader said in 2010 that he had sung patriotic songs with Anna Chapman, one of 10 Russian agents deported from the United States as part of the countries' biggest spy swap since the Cold War.
Butina's return to Russia has sparked speculation that Paul Whelan, a former U.S. Marine held in Russia since December last year on espionage charges, could also be sent home.
But there are no signs suggesting Whelan could be freed anytime soon. His pre-trial detention was extended earlier this week until late December.
Butina, released from a Florida prison on Friday after serving most of her 18-month sentence, did not comment on her case in her comments to the reporters at the airport.
But in an interview with Russian state media apparently recorded during the flight, Butina insisted on her innocence.
"Some actions will need to be taken with regards to the outrage that happened to me," Russia’s state-run RIA news agency quoted her as saying.
Rebecca Ross, spokeswoman at the U.S. Embassy in Moscow, said Butina had committed a crime.
"She was arrested and presented with the evidence, pleaded guilty and was sentenced," Ross wrote on Twitter.
Butina had been scheduled for release from the low-security prison in Tallahassee in early November, but a change in federal law moved up her release date based on credit for good behaviour, according to her attorney in the United States, Robert Driscoll.
Her 18-month sentence included nine months she spent incarcerated after her July 2018 arrest.