ISTANBUL - An opposition leader from the Central Asian nation of Tajikistan was shot dead by an unknown gunman on a street in Istanbul late Thursday, Turkish media reported on Friday.

Umarali Kuvvatov, head of the “Group 24” opposition group, was killed with a gunshot wound to the head in Istanbul’s conservative Fatih district, said the Dogan news agency.

The assailant fled the scene, it said.

Kuvvatov, an oil businessman, was one of the most outspoken critics of the hardline regime of President Emomali Rakhmon and was wanted by Dushanbe on fraud charges which his supporters claimed was politically motivated.

His movement Group 24, which is based outside Tajikistan, was banned in October last year by the country’s Supreme Court after the government labelled it as an “extremist organisation.”

Tajik authorities blocked the movement’s website, as well as hundreds of others, after Group 24 used social media to call for a mass anti-government protest in Dushanbe in October.

Kuvvatov, 47, fled Tajikistan in 2012 for Dubai and had been living in Turkey with his wife and children since early 2013. Tajikistan in January had formally asked Turkey to extradite him.

Tajikistan, an impoverished Muslim nation of some eight million people, has been led since 1992 by former Soviet apparatchik Rakhmon, who has ruled with an iron fist after seeing his republic shattered by civil war when the Soviet Union broke up.