A Russian court has sentenced a Crimean Tatar man to 12 years in prison, drawing swift condemnation from Ukraine for what Kyiv called a politically motivated ruling.

Lawyers for Ruslan Zeytullayev said that in an April 26 verdict, a military court in the Russian city of Rostov-on-Don convicted their client of establishing a cell of the Islamic group Hizb ut-Tahrir in Crimea.

Hizb ut-Tahrir is banned in Russia, which seized control of Crimea from Ukraine in 2014 and has prosecuted many opponents of the takeover -- including members of the Muslim Crimean Tatar community -- on what rights groups say are false charges.

Ukrainian Foreign Ministry spokeswoman Maryana Betsa said the ruling was politically motivated and urged other countries to take Moscow to task over Zeytullayev's trial.

"The so-called ruling is based on fabricated accusations. We demand the release of Zeytullayev," Betsa said on Twitter. "We will [call on] our partners to increase diplomatic pressure on the Russian Federation."

The 12-year sentence came in a retrial that was launched after Russian prosecutors contended that the initial sentence was too lenient.

In September, the same court had convicted Zeytullayev and three other Crimean Tatars of being members of Hizb ut-Tahrir and sentenced them to prison terms ranging from five to seven years.

Prosecutors said at the time that Zeytullayev deserved harsher punishment for being "a founder" of a Hizb ut-Tahrir cell.

Russia has been heavily criticized by international rights groups and Western governments for its treatment of the members of the indigenous Turkic-speaking Crimean Tatar minority since it took over the Black Sea peninsula in March 2014.

Rights activists say Crimean Tatars have been arrested, abducted, and in some cases killed in a campaign to punish the group for largely opposing the takeover and neutralize it as a potential political and social force.

Crimean Tatar self-government organizations have been declared illegal.

Russia seized control of Crimea after sending in troops and staging a referendum considered illegitimate by the United States and a total of 100 UN member states.

The United States, European Union, and other countries imposed sanctions on Russia over the takeover of Crimea and say they will not be lifted until it is returned to Kyiv's control.