A prominent environmentalist says she has fled Russia, moving with her family to Estonia out of fear that government harassment could take her children away from her.

Yevgeniya Chirikova is best known for a 2010 campaign opposing the construction of a highway outside Moscow. Her activism cost some of Russia's most powerful men billions of dollars in contracts.

The mother of two told The Associated Press on Monday that she left mostly because of threats by social services to take her children away from her.

Chirikova, who won the prestigious Goldman Award in 2012, also said she does not want to pay for Russia's "military aggression against Ukraine" with her taxes.

Chirikova's departure follows the emigration of several prominent government critics in recent years.