Human Rights Watch (HRW) says that Russian police are "systematically" interfering with attempts by opposition leader Aleksei Navalny to campaign for the March 2018 presidential election.
In a September 6 statement, the international human rights monitor said that a "pattern of harassment and intimidation" against Navalny’s campaign was "undeniable."
"Police across Russia have raided Navalny's campaign offices, arbitrarily detained campaign volunteers, and carried out other actions that unjustifiably interfere with campaigning," HRW said.
The New York-based rights group said radical Russian nationalists and groups that support President Vladimir Putin have "physically attacked and threatened" Navalny’s campaigners.
It said "the extensive police harassment, and attacks on the local offices and campaigners by radical nationalist and pro-Putin groups" during the spring and summer of 2017, "clearly aim to intimidate campaigners and stifle the campaign."
HRW also said official investigations into violence against the anticorruption activist's campaign "have not been effective."
The rights group said that there have been police crackdowns and violence against Navalny’s campaign workers in Moscow, St. Petersburg, Kazan, Krasnodar, Rostov-on-Don, Kaliningrad, Irkutsk, and Khabarovsk.
"Police have searched campaign offices, seized campaign materials or equipment, and intercepted and confiscated shipments of campaign materials under vague pretexts of 'extremism' allegations," it said.
"Authorities have refused to authorize Navalny's campaign sidewalk displays, and have detained campaigners on groundless charges of holding unauthorized public gatherings, and for alleged unlawful campaigning activity," it said.
'Politicized, Unfair Trial'
Navalny announced in December 2016 that he intended to run in the election. Since then, he has opened more than 60 campaign offices in different regions of Russia.
In June, however, the Central Election Commission said that Navalny is ineligible to run for public office because of a financial-crimes conviction.
Human Rights Watch said the conviction was "the result of a politicized, unfair trial."
Putin has not announced whether he will run in the presidential election, but is widely expected to seek and secure a fourth term.
Hugh Williamson, Europe and Central Asia director at HRW, said "the use of specialist police and the label of 'extremism' as a pretext for raids, confiscations, and detentions suggests that authorities think it's 'extremist' just to challenge President Vladimir Putin.”
Williamson said "Russian authorities should let Navalny's campaigners work without undue interference" and should "properly investigate attacks against them by ultranationalists and pro-government groups."