Russia on Friday added respected journalist and Nobel Prize co-recipient Dmitry Muratov to its list of foreign agents, a label authorities commonly use to stifle critics.

Russia's Ministry of Justice said Muratov "used foreign platforms to disseminate opinions aimed at forming a negative attitude towards the foreign and domestic policy of the Russian Federation."

The label, which is reminiscent of the term "enemies of the people" of the Soviet era, requires individuals or groups to disclose sources of funding.

It also compels them to mark all publications -- including social media posts -- with a tag.

The ministry also accused Muratov of creating and distributing content from other foreign agents.

Moscow has stepped up efforts to stamp out dissent since launching the assault on Ukraine, with most high-profile opponents in exile or behind bars.

Muratov was seen recently in Russia, being part of the legal team defending his friend Oleg Orlov, co-chair of Russia's human rights organisation Memorial.

In 2021, Muratov who works as the chief editor of Russia's top independent publication Novaya Gazeta, shared the Nobel Peace Prize with the Philippines' Maria Ressa for their respective fights for freedom of expression.

Since 2000, Novaya Gazeta has seen six of its journalists and contributors killed, including investigative reporter Anna Politkovskaya, who was shot dead in Moscow on President Vladimir Putin's birthday.