Putin says US jailing of Russian agent Maria Butina 'arbitrary'

Russian President Vladimir Putin on Saturday slammed the jailing of agent Maria Butina in the United States as "arbitrary", adding that he did not understand why she had been incarcerated.

"There is nothing we could accuse her of, but to make this case not look completely ridiculous, she was sentenced to 18 months in prison," he told journalists on the sidelines of a summit in Beijing.

Butina pleaded guilty in a Washington court on Friday to one count of conspiracy to act as an agent of a foreign government without registering.

"It is in fact arbitrary," Putin said. "We don't understand why she was sentenced." It made her the only Russian arrested and convicted in the three-year investigation of Moscow's interference in US politics.

The leader of a small Russian gun rights group, the 30-year-old used her ties to the National Rifle Association to build a network of powerful Republican contacts.

US prosecutors said she was sending back reports to a high-level Russian government official.

Moscow lashed out after the sentencing, calling the US accusations "totally invested" and the conviction a "shameful stain" on the US judicial system.