The United States has called on "Russian occupation" authorities in Crimea to release prominent Tatar leader Ilmi Umerov and vacate his conviction for separatism.

The State Department denounced Umerov's conviction and two-year prison sentence in an October 3 statement, saying, "This compounds past injustices in the case, including his confinement for several weeks of punitive psychiatric treatment in 2016."

The statement added that the Crimean Peninsula, which Russia illegally annexed in March 2014, "remains an integral part of Ukraine, and the United States remains steadfast in its support for the territorial integrity and sovereignty of Ukraine."

Russian-appointed judges in Simferopol, the Crimean capital, found Umerov guilty on September 27 and sentenced him to two years in a colony settlement, a penitentiary in which convicts usually live near a factory or farm where they are forced to work.

The sentence was harsher than that sought by prosecutors, who had recommended a three-year suspended sentence with a ban on all public activities for three years.

'Egregious' Rights Violation

Umerov said he would appeal the ruling all the way to the European Court of Human Rights.

The European Union called Umerov's sentencing "a serious violation of his human rights, another example of persecution of the Crimean Tatar community."

Ukraine described the verdict an "illegal and politically-motivated sentence" which it said violated Umerov's human rights.

The court ruling followed a trial that Human Rights Watch called "ruthless retaliation" for his opposition to Moscow's takeover of the peninsula.

Umerov, a deputy chairman of the Mejlis, the Crimean Tatars' elected representative body, has been an outspoken critic of Russia's seizure of the Black Sea peninsula from Ukraine in March 2014 and its subsequent crackdown on Crimean Tatars.

Russia's Federal Security Service (FSB) detained Umerov, who suffers from diabetes and Parkinson's disease, in May 2016 in Crimea and charged him with separatism.

He was confined to a psychiatric hospital in August 2016 by the Russian-imposed authorities in Crimea, a decision condemned by Human Rights Watch as "an egregious violation of his rights."

Speaking at the trial on September 20, the 60-year-old Umerov said that the charges against him aimed "to punish those who oppose the annexation."

The charges stem from a March 2016 live interview with the Crimean Tatar TV channel ATR, which was later posted on YouTube. Russian authorities shut down the station in April 2015, and it relocated to Kyiv.

Umerov said the translation of the interview into Russian from Tatar was poorly done and distorted his remarks.

'Persistent Campaign Of Repression'

The Russian authorities have outlawed the Mejlis after deeming it extremist, part of what rights groups and Western governments say is a persistent campaign of oppression targeting Crimean Tatars and other citizens who opposed Moscow's takeover.

Another Mejlis deputy chairman, Akhtem Chiygoz, was convicted of organizing an illegal demonstration and sentenced to eight years in prison on September 11 after what Amnesty International called a "sham trial."

Umerov’s conviction follows a similar ruling in Crimea on September 22 against RFE/RL contributor Mykola Semena.

In a report issued on September 25, the UN Human Rights Office said that Russia's occupation of the region has been marked by disappearances and torture, infringements of the Geneva Conventions, and violations of international law.

The European Parliament is scheduled to debate and vote this week on a resolution highlighting what European lawmakers say are human rights abuses by authorities in Crimea.

The October 5 session in Strasbourg will focus on the arrests and trials of figures like Semena, Chiygoz, and Umerov since Russia's annexation of the peninsula.

Following the ouster of a Moscow-friendly Ukrainian president in February 2014, Russia seized control of Crimea by sending in troops and staging a referendum deemed illegitimate by at least 100 countries in the United Nations.

The European Union, along with the United States and other Western countries, have imposed sanctions against Russia in response to the takeover of the Ukrainian territory.