TALLINN, Estonia (AP) — A former Russian tycoon jailed in Azerbaijan on charges stemming from his time as a top separatist figure in the Karabakh region has gone on a hunger strike, his family said Friday.

Ruben Vardanyan started the fast two weeks ago to press demands for a speedy trial, news agencies cited the family as saying.

Vardanyan cofounded Troika Dialog, once among Russia’s top investment banks, and amassed wealth estimated at reaching $1 billion.

In 2022, he renounced his Russian citizenship and moved to the Karabakh region, parts of which were run by ethnic Armenians who sought to split away from Azerbaijan.

He became the region’s state minister, the equivalent of premier, but was dismissed in 2023. Azerbaijan, which had regained control of large parts of Karabakh in a 2020 war had been calling for him to be ousted.

Azerbaijan took full control of the rest of Karabakh in a lightning offensive in September 2023 that drove almost all of the region’s 120,000 Armenians to flee.

Vardanyan was arrested while trying to cross into Armenia and was charged with financing terrorism and establishing armed groups.