The Russian foreign ministry said on Wednesday that it was "deeply disappointed" by the extradition of travel blogger Alexander Lapshin from Belarus to Azerbaijan.
In a statement, the ministry said that the man's extradition was "inconsistent with the spirit of allied relations between Russia and Belarus."
"We intend to continue taking all necessary measures to defend the rights and legal interests of the Russian citizen for the purpose of his speedy reunion with his family," said the Russian ministry.
Mr. Lapshin was sent to Baku on February 7, the day when the Supreme Court of Belarus rejected his appeal against extradition.
Mr. Lapshin, 40, who is a citizen of Russia and Israel, was arrested in Minsk at Azerbaijan's request in December last year. Baku wanted the man handed over to face criminal charges over his visits to the disputed Nagorno-Karabakh region.
The extradition request was granted by the Belarusian Prosecutor General's Office on January 17.
Mr. Lapshin is said to be accused of visiting Nagorno-Karabakh several times without Azerbaijan's permission.
Reports have it that the true reason for the case against the blogger is his critical posts about Azerbaijan and its president, Ilham Aliyev.
Russian Foreign Minister Sergei Lavrov said this past January that Moscow objected to Mr. Lapshin's extradition.
Mr. Lavrov said that Russia opposed the practice of prosecuting people for "visiting some area or other in some region or other" and the extradition of Russian citizens arrested in some country or other to a third country.
However, Alyaksandr Lukashenka said last week that he saw no reasons for refusing to extradite the blogger.