Ukrainian President Petro Poroshenko has wished a happy birthday to Ukrainian military aviator and parliamentarian Nadia Savchenko, whom Russia has sentenced to 22 years in prison.

"I would like to cordially wish a happy birthday to our Nadia, a symbol of faith in victory over the aggressor! I am doing everything possible so as to greet the Ukrainian Hero personally on home turf," Poroshenko said on Facebook on Wednesday morning.

Foreign Minister Pavlo Klimkin also sent birthday greetings to Savchenko.

"On Nadia's birthday, I will recall #FreeSavchenko and other political prisoners of ours. And I wish Savchenko to be happy. She deserves this more than anybody else," Klimkin said on Twitter.

Savchenko was born in Kyiv on May 11, 1981.

It was reported on Tuesday that Savchenko's mother had come to Rostov-on-Don to wish her daughter a happy birthday on Wednesday.

Savchenko has been held in Russian custody since July 2014 after being kidnapped by Russia-backed separatists and illegally taken across the Ukrainian border.

The Donetsk City Court in Russia's Rostov region found Savchenko guilty in a case dealing with the killing of Russian journalists Igor Kornelyuk and Anton Voloshin and sentenced her to 22 years in prison on March 22. The court also found her guilty of attempted murder and illegal crossing of the Russian border.

At the end of April, Savchenko and her defense lawyer Nikolai Polozov filled out documents for her extradition to Ukraine. Another lawyer for Savchenko, Mark Feygin, said Savchenko did not admit her guilt in filling out the extradition documents. "In filling out the documents, Nadia did not admit her guilt anywhere," Feygin told Interfax.