Ukrainian President Petro Poroshenko has said he is ready to secure the release of celebrated Ukrainian pilot Nadia Savchenko through a prisoner exchange with Russia.

The Russian trial of Savchenko on allegations that she aided the 2014 killing of two Russian journalists in eastern Ukraine wrapped up on March 9.

She rejects the charges and has been on a hunger strike since March 3 to protest her detention.

Earlier in the day, Russian Foreign Ministry spokeswoman Maria Zakharova said talks on a prisoner exchange could not take place "in theory or in practice" until the verdict, which is expected on March 21.

Savchenko"s detention and hunger strike provoked an outpouring of protests in Ukraine and Russia on March 9 and prompted world leaders to call for her immediate release.