A Crimean Tatar leader sentenced to two years in jail for opposing Russian rule in the annexed territory has said he will not appeal to the Kremlin for mercy, despite illnesses that mean his life could be at risk in prison.

“There is little hope for justice through an official appeal, and I will definitely not be making any appeals for clemency,” Ilmi Umerov told the Guardian by telephone from his Crimea home, saying he did not want to beg to his oppressors.

Umerov, who was found guilty of “separatism” this week by a court in Crimea, has been diagnosed with stage three Parkinson’s disease, has type 2 diabetes and underwent a heart operation several years ago.

His lawyer, Mark Feygin, said he was “physically unable” to withstand a prison term, calling it “effectively a death sentence”. He said he would mount a legal appeal, though he believed the case was politically motivated and only a political decision in Moscow would have an effect on the outcome.

Umerov was tried for comments made to a Crimean Tatar television station last year in which he decried the 2014 annexation of the territory. The court claimed the words contained a call to change Russia’s borders by force, but Umerov and Feygin said his words had been incorrectly translated from Crimean Tatar language into Russian.

“It’s absolutely clear to me that I was on trial for nothing more my refusal to shut up about my belief that Crimea is part of Ukraine, and the fact that I call an annexation an annexation and an occupation an occupation,” said Umerov.

Moscow’s takeover of Crimea was supported by many in the region, but critics of the annexation have been dealt with ruthlessly. Independent media has been shuttered and there has been a wave of arrests and threats directed against the Crimean Tatars, the majority of whom opposed Russian rule for historical reasons.

Joseph Stalin had the entire Crimean Tatar population deported in 1944 for alleged collaboration with the Nazis, and they were only allowed to return to Crimea in 1988.

Umerov was the long-standing mayor of Bakhchiserai under Ukrainian rule, but resigned several months after the Russian takeover, saying he would not serve a government he believed to be an occupying regime.

Since then, he has been targeted by authorities, culminating in this week’s verdict. In an unusual move, the judge decided to impose a harsher sentence than state prosecutors had requested, imposing a two-year term in a penitentiary settlement rather than the suspended sentence for which the prosecutors had asked.

Feygin said it was “extremely irregular” for the judge to act this way, and also said it was unusual that Umerov had been allowed to remain free until the appeals process was concluded.

“None of this is normal and it’s completely obvious that this was ordered from above,” he said. “I think it’s part of a Kremlin game. They want western leaders to call Putin and start bargaining over it.”

Umerov said he had no regrets about not fleeing Crimea when he had the chance, insisting that the peninsula was his homeland. “Even if someone gave me a safe corridor to leave now, I would not accept,” he said.

The case has been widely derided by rights groups, including the Moscow-based Memorial, which called it “illegal and politically motivated”. The European Union said the conviction was in breach of international humanitarian law and called on Russia to reverse it.