Ukrainian military pilot Nadia Savchenko, who is in detention in Russia after being accused of involvement in the death of two Russian journalists, has gone on a hunger strike.

A Savchenko lawyer, Nikolai Polozov, said in a tweet that the detainee announced the hunger strike in a Donetsk city court in Russia's Rostov region on December 17.

"Nadia Savchenko has gone on a hunger strike until the end of the trial," Polzov said, adding that she will begin a "dry" hunger strike when she is sentenced, meaning that she will refuse both food and water.

"She demands to be released," he said.

Polozov said the court also agreed with a prosecutor's request to extend her detention until April 16.

Russian officials say Savchenko helped relay information to artillery units that fired near a location in eastern Ukraine where two Russian journalists were killed by artillery fire.

Savchenko -- who is also being charged with illegally crossing the Russian border -- says she was captured by pro-Russian separatists in July 2014 and forcibly taken to Russia.

If found guilty, Savchenko faces up to 25 years in prison.

The 34-year-old has spent over a year in custody in Russia, during which time she has already protested her detention by going on an extended hunger strike.

Based on reporting by TASS and Interfax

