People hold Ukrainian, Crimean and Crimean Tatar flags during rally in support of Ukraine's territorial integrity, in Kyiv's Independence Square, March 23, 2014.
FILE - People hold Ukrainian, Crimean and Crimean Tatar flags during rally in support of Ukraine's territorial integrity, in Kyiv's Independence Square, March 23, 2014.

MOSCOW - A Russian court on Tuesday handed down prison terms of up to 19 years to six Crimean Tatar men for membership of a banned "terrorist organization", ending a three-year case denounced by rights groups.

Six residents of Crimea, the Black Sea peninsula Moscow annexed from Ukraine in 2014, were arrested in 2016, accused of belonging to Islamist group Hizb ut-Tahrir, which is banned in Russia, and plotting to overthrow the government.

A military tribunal in the southern city of Rostov sentenced Muslim Aliyev, Enver Bekirov, Vadim Siruk, Refat Alimov, Arsen Dzhepparov and Emir-Usein Kuku to prison terms of between seven and 19 years for various roles in the group, according to Russian news agencies.

All six had denied the charges, and rights groups denounced their case as politically motivated against Crimean Tatars, a mainly Muslim ethnic group who make up about one-tenth of the peninsula's population and were viciously persecuted under Stalin during World War II.

Amnesty International, which has recognized Kuku as a prisoner of conscience, said Tuesday the verdict — including 12 years for Kuku — was of "remarkable cruelty."

"This decision brings to a close what can only be described as a sham trial," the organization’s Eastern Europe and Central Asia director Marie Struthers said.

Defense lawyers in the case have said that the prosecution relied on flimsy evidence provided by obscure linguistic experts suggesting that the accused engaged in Islamist propaganda and recruited members into Hizb Ut-Tahrir.

During the trial, the men said the case amounted to ethnic and religious persecution.

Russia has a tough policy towards Hizb Ut-Tahrir, which seeks to establish an Islamic caliphate through non-violent means, and has particularly cracked down on alleged members since the annexation of Crimea.

The organization is not banned in Ukraine, and was active on the peninsula before the annexation.

According to the Russian rights organization Memorial, more than 300 people across the country are currently in custody or have been sentenced for their alleged association with Hizb Ut-Tahrir.

More than 60 were sentenced to 15 years or more behind bars, Memorial says.

Crimean Tatars say Russian authorities are using legislation criminalizing Hizb Ut-Tahrir to prosecute members of their community for rejecting the annexation of Crimea and resisting Russian rule.

The close-knit community has protested over the multiple cases against Crimean Tatars, including in July, when dozens opposing a different case involving Hizb Ut-Tahrir were detained outside the Supreme Court in Moscow.