Outspoken Russian journalist and environmentalist Mikhail Beketov, who was beaten nearly to death in 2008 in an attack thought to be linked to his activism, died on Monday, his lawyer said.

Beketov, who campaigned against the logging of a Moscow region forest and edited an independent newspaper in the suburb of Khimki, was assaulted in 2008 and had been slowly regaining his health after multiple surgeries.

His death was completely unexpected, and occurred during a "routine hospitalisation," his lawyer Stalina Gurevich told AFP.

"His heart stopped," she said.

The attack left the muscular Beketov, a veteran paratrooper who had worked as a war correspondent in Afghanistan and Chechnya, wheelchair-bound and unable to speak due to brain damage.

However, he had recently began to speak and walk again.

Beketov, who was 55 when he died, was the first person to spearhead the campaign to save the Khimki forest, where the government wants to lay a highway linking Moscow and St. Petersburg.

His newspaper Khimkinskaya Pravda published critical articles about the local mayor and corruption schemes surrounding the project.

A probe into Beketov's beating never revealed the perpetrator of the crime. When he told journalists he suspected the local mayor to be involved in attempts on his life, the mayor sued him for slander.

"The attack on Mikhail Beketov will be explained some day, but not now," said veteran human rights activist Lyudmila Alekseyeva.

"One can only admire the tenacity and heroism with which she continued to defend people's rights, despite his difficult condition," she told the Interfax news agency.

"Misha was the first who showed me that corruption was behind the Khimki forest (road project)," tweeted activist Yevgenia Chirikova, who picked up the campaign after Beketov's incapacitation and took it to a national level.

"The person who ordered the attack on him is still at large," she said.

The anti-logging campaign in Khimki has slowly fizzled after the government decided to build the road despite constant protests and attacks on activists who claimed the works are illegal.