By Andrew Osborn and Tom Balmforth
MOSCOW - Russia declared the "Proekt" investigative news outlet an "undesirable" organisation on national security grounds on Thursday, banning its activities in the latest blow against media who look into areas the authorities say are off limits.
The move, part of a wider crackdown ahead of parliamentary elections in September on media the authorities view as hostile and foreign-backed, targets an outlet which has published a series of deeply researched and unflattering investigations into Russia's ruling elite.
In a statement, the General Prosecutor's Office said that Proekt's activities constituted a "threat to constitutional order and security". It described the outlet as a U.S.-based non-governmental organisation.
Authorities on Thursday also labelled eight journalists as "foreign agents", including reporters from Proekt, as well the Open Media outlet, according to the Interfax news agency.
The decision to declare a media outlet undesirable appears to be a serious escalation of the crackdown against media the authorities see as hostile.
The justice ministry lists 40 groups that have received the same designation. None of them are media outlets.
Under a 2015 law, members of "undesirable organisations" can be fined or jailed for up to six years for ignoring the ban.
The Kremlin has previously said it does not believe a media crackdown is underway and has described the media market as vibrant with many different outlets to choose from.
Proekt came under pressure last month when police raided the homes of two if its journalists and detained a third as part of a criminal investigation into suspected slander.
Police seized laptops and other property from the homes of Roman Badanin, the editor-in-chief of Proekt, and its reporter Maria Zholobova, the outlet said. Its deputy editor-in-chief, Mikhail Rubin, was also detained.
Several non-state outlets have complained of mounting government pressure in recent months.
Online news site Newsru announced its closure earlier this year for economic reasons, saying that advertisers were steering clear of it because its story selection did not follow pro-Kremlin state media.
News website VTimes announced its closure last month after being labelled a "foreign agent", a designation it said had scared away its partners, ruined its business and made it harder to report the news.
U.S. broadcaster Radio Free Europe/Radio Europe has had its Moscow bank accounts frozen and been fined heavily for refusing to comply with a rule requiring it to publish disclaimers on its content saying it fulfils the function of a foreign agent.
Latvia-based independent outlet Meduza has also been labelled a foreign agent.