Ukrainian diplomats have been admitted to a detention facility in Russia's Rostov-on-Don, to meet with Ukrainian military aviator Nadia Savchenko, says her defense lawyer Nikolai Polozov.

"The head of the detention center's administration came out, and invited the consuls to Nadia. I'll go after them," Polozov said on Twitter on Tuesday.

Following a telephone conversation between Russian President Vladimir Putin and Ukrainian President Petro Poroshenko, Putin's press secretary Dmitry Peskov announced Savchenko's meeting with the Ukrainian consul general in Rostov-on-Don.

The Donetsk City Court in Russia's Rostov region sentenced Savchenko to 22 years in a general security penitentiary on March 22.

The judgment took legal effect on April 5. Savchenko started a hunger and a thirst strike on April 6.