Ukraine together with its partners will step up pressure on Russia to free political prisoner Volodymyr Balukh, who went on a hunger strike on March 19.

"We are worried about Balukh's health and together with our partners we will increase pressure on the Russian Federation regarding his release," the Ukrainian Foreign Ministry's spokeswoman Mariana Betsa wrote on Twitter on Saturday.

As reported, Ukrainian farmer Balukh was arrested on December 8, 2016 in his house in the village of Serebrianka of Rozdolne district of Crimea temporarily occupied by the Russian Federation. Russian authorities charged him with possession of ammunition.

Crimea's Rozdolne District Court sentenced Balukh to three years and seven months of imprisonment in a low-security penal colony and to a fine of 10,000 Russian rubles. Balukh's defense team said the case was fabricated, and his verdict would be appealed in courts of higher instances.

Balukh has been on a hunger strike since March 19.