A verdict on Savchenko's case is expected around March 21
U.S. President Barack Obama and top diplomats representing G7 countries in Ukraine are calling on Russia to release Ukrainian fighter pilot Nadiya Savchenko.
In a telephone conversation with Russian President Putin, according to media reports, Obama said Savchenko must be released as part of the Minsk peace agreement.
Savchenko is on trial for involvement in the deaths of two Russian journalists as well for crossing Russia's border illegally.
Many U.S. and E.U. politicians have called the trial a sham. Savchenko says she was smuggled into Russia by militant forces an hour before the journalists were killed.
A verdict is expected around March 21.