A Russian environmentalist working on a report about impact of the Sochi Olympic Games was sentenced to three years in a penal colony Friday for causing damage to property, in what he said was an attempt to scare other activists.

A judge in the southern Black Sea town of Tuapse which borders Sochi ruled that Evgeny Vitishko had violated his parole and turned a suspended sentence of three years he is currently serving into a real one.

Once the decision goes into effect he will have to go to a penal colony, but he has 10 days to appeal, Vitishko told AFP.

A geologist and member of regional group Environmental Watch on North Caucasus, Vitishko is currently working on a report that will highlight the negative environmental impact of Olympic construction on Sochi's nature.

"The ruling is a show of force for other environmental activists," Vitishko told AFP.

The NGO he is a part of has been under pressure lately, with one activist earlier this year receiving political asylum, another facing a defamation lawsuit, and several more getting house visits by police recently warning them against any protests.

In June 2012 Vitishko and Suren Gazaryan, another prominent local environmental activist, received three-year suspended sentences for causing $4,000 worth of property damage to a fence in a forest, out of what the court called motives of hooliganism.

However the group says the fence was illegally erected in a public forest around a residence belonging to the governor of Krasnodar region, Alexander Tkachyov.

In an inspection in late 2011, a group of activists opened up a section of the fence and uncovered logging of protected species of trees.

Some people in the group also wrote slogans like "The forest is for everybody" on the fence, made of corrugated metal.

Gazaryan fled Russia in late 2012 and now resides in Estonia. Vitishko meanwhile had to abide to strict rules of his suspended term, with parole officials checking his movements constantly.

The parole service in court said Vitishko violated the rules twice in the past eight months and requested to imprison him, his lawyer Alexander Popkov said. He called it a "technicality" that does not prove he is a systematic offender.

Environmental Watch on North Caucasus has been one of the most vocal critics of construction ahead of the Winter Olympic Games in Sochi to be held on February 7 to 23.