Opposition leader Alexei Navalny, who is barred from using the Internet under the terms of his house arrest, has used his blog to condemn Russia's incursion into Ukraine.
Navalny passed a handwritten letter onto members of his Anti-Corruption Fund, who in turn published his message on his LiveJournal account.
Navalny said that he cannot support Russia's attempts to annex Crimea, pointing to the 1994 Budapest Treaty that Russia signed, along with the U.S. and Britain, which guaranteed Ukraine's territorial integrity and sovereignty in exchange for Kiev eliminating the country's nuclear arsenal.
"Altering the borders of states in Europe by military force is unacceptable," Navalny said. "This will not lead to anything good."
He also criticized plans to hold a referendum in Crimea on Sunday that will pose the question of whether the peninsula should become part of Russia. He said that the referendum has been set up at too short notice and that the atmosphere of "agitation" is not conducive to a fair vote.
As a way out of the crisis, Navalny suggested that Kiev should grant Crimea greater autonomy while remaining part of Ukraine, guarantee the right to speak Russian in Ukraine, keep Ukraine out of NATO, and let the Russian Black Sea fleet remain in the peninsula free of charge.
Navalny was placed under house arrest in February after a Moscow court ruled that he had repeatedly violated travel restrictions imposed on him for the duration of a fraud inquiry against him and his brother, Oleg.
The Navalny brothers are suspected of embezzling 26 million rubles ($720,000) from the Russian branch of French cosmetics company Yves Rocher.
His Twitter account has been continually updated during his period of house arrest, which expires on April 28.