Two leading Tatar activists sentenced for their political activities by Russian authorities in annexed Crimea have been freed and have flown to Turkey, their family and lawyers said on Wednesday.

"Ilmi Umerov and Akhtem Chiygoz are freed and most likely have already landed in Ankara," Umerov's wife Maye told AFP.

Refat Chubarov, the head of the Crimean Tatars' banned assembly, the Mejlis, said that the two men had been freed following recent talks between Russian President Vladimir Putin and Turkish leader Recep Tayyip Erdogan.

"Active work over this issue has been going on for two weeks. This is the result of recent talks between Erdogan and Putin," Chubarov told AFP from the Ukrainian capital Kiev where he lives in exile.

"Various politicians including... German Chancellor Angela Merkel played a role in freeing Umerov and Chiygoz."

Erdogan has pledged to support Crimea's Turkish-speaking Tatar minority -- who have maintained their Turkic language and Sunni Muslim religion in a region where the majority is Russian-speaking and orthodox.

"Two more hostages, two more Ukrainian political prisoners have gained freedom," defence lawyer Nikolai Polozov said on Twitter.

"This is a natural result of titanic efforts (and) successfully conducted legal, political and diplomatic work."

In September, a court sentenced Umerov to two years in a penal colony on charges of "separatism".

His defence argued that the 60-year-old activist, who suffers from Parkinson's disease, diabetes and other conditions, would not be able to serve a prison term.

He was allowed to remain home pending his appeal.

Umerov was the deputy chairman of the Mejlis, which the Russian authorities have banned as extremist.

Chiygoz, 52, another prominent Crimean Tatar leader, was arrested in 2015 and this past September was jailed for eight years over deadly clashes at a rally, in a trial Amnesty International rights group called a "sham."

The two men are two of the Crimean Tatars' most high profile community leaders and have irked Moscow by opposing its annexation of the peninsula from Ukraine in 2014.

The Kremlin-backed authorities have launched a vicious crackdown on Tatars since Crimea's annexation.

The Crimean Tatars are a Muslim people native to Crimea who were deported under Stalin and only returned to the peninsula in the 1990s.

In May last year, Russia charged Umerov with making public calls to change Russia's borders after he said on Crimean Tatar television that Crimea should be returned to Ukraine.

His trial began in 2016, when he was forcibly detained in a psychiatric hospital for three weeks to undergo testing.

Source: AFP