(Reuters) - Nobel Prize-winning Russian journalist Dmitry Muratov will mount a legal challenge to try to overturn his designation as a "foreign agent" by the authorities in Russia, Novaya Gazeta, the newspaper he edits, said on Monday.
Russia's justice ministry on Friday added Muratov, a veteran editor and co-laureate of the 2021 Nobel peace prize, to the growing list of people it has formally labelled "foreign agents" - a designation used to stigmatise and complicate the life of people it deems to be working against Russian state interests.
It said Muratov, who sold his Nobel medal at auction to help Ukrainian child refugees, had "created and disseminated material (produced by) foreign agents and used it to spread negative opinions of Russia's foreign and domestic policies on international platforms".
Novaya Gazeta, which is famous for its investigations which have sometimes taken aim at the Kremlin, government policy and top officials, said on Monday Muratov would temporarily step aside from his role as editor-in-chief in order to challenge his designation through the courts.
"Muratov categorically disagrees with the decision of the Ministry of Justice and is filing a lawsuit," Novaya Gazeta said in a statement.
"At his own request, the editorial board is suspending Dmitry Muratov as editor-in-chief for the duration of the legal proceedings. Sergei Sokolov has been appointed acting editor-in-chief."
It said Muratov had been targeted by the authorities for his opinions and beliefs, something it said ran counter to constitutional guarantees about freedom of thought and speech.
The justice ministry has significantly expanded its "foreign agent" list since Russia launched what Moscow calls its "special military operation" in Ukraine in February 2022, using it to tar people and organisations who publicly criticise or question the war.
Journalists designated "foreign agents" must include a disclaimer about their status on every piece of work, are subject to greater official scrutiny and financial checks, and media given the same label have seen Russia-based funders and sponsors withdraw their support.
Novaya Gazeta suspended publication in 2022 in response to legislation imposing harsh penalties for discrediting the Russian military's actions in Ukraine. Many of its journalists have since regrouped with a new publication in Latvia.
(Reporting by Andrew Osborn; Editing by William Maclean)