The court in Moscow handed down the sentence against Roman Udot on November 28 after finding him guilty of threatening the life of two journalists working for state-owned NTV television channel.

Udot has rejected the charges and said the case against him was in retaliation for an investigation into alleged election fraud.

"This case needs to be examined in light of the stalking and smear campaign by the pro-Kremlin broadcaster," Hugh Williamson, Europe and Central Asia director at Human Rights Watch (HRW), said. "The political motivation behind the prosecution becomes clear."

In a statement, the New York-based watchdog said NTV was "notorious for its smear campaigns against human rights activists and political opposition," adding that the broadcaster had "repeatedly and viciously targeted Udot and stalked his family members."

Udot was a board member of Golos, one of Russia's most prominent election-monitoring organizations.

His prosecution stems from a March 2018 incident at a Moscow airport where two NTV reporters descended on the activist and peppered him with questions on camera, which led to an exchange of insults.

In May this year a court ordered house arrest for Udot.

Memorial human rights center designated him a “political prisoner” and called his arrest an attempt by the authorities to hinder the agency's activities during Russia's regional and local elections in September.

An appeals court later replaced Udot’s house arrest with a curfew and a ban on communicating with other people involved in the case, and using a cell phone and the Internet.

“There is little doubt that his prosecution was meant to punish him for his work at Golos and to discourage others from involvement in election-monitoring efforts,” Williamson said.

Golos has also been targeted by NTV in the past and has been repeatedly pressured by authorities.

The group was labeled a "foreign agent" in 2013 under a law aimed at restricting nongovernmental organizations ability to receive foreign funding.