Belarusian dissident Vitaly Shishov was on Tuesday found hanged in a park close to where he lived in Ukraine, with police opening a murder probe and supporters accusing the regime of Alexander Lukashenko of killing the activist who helped his compatriots flee repression.

Shishov, 26, headed the Belarusian House in Ukraine, a non-governmental organisation involved in everything from helping fellow compatriots settle in Ukraine to staging anti-regime protests.

Belarus strongman Alexander Lukashenko has been cracking down on any form of dissent since mass protests erupted after last year's elections
Belarus strongman Alexander Lukashenko has been cracking down on any form of dissent since mass protests erupted after last year's elections AFP / STRINGER

He went jogging in Kiev on Monday morning but did not return and could not be reached on his mobile phone.

Belarus strongman Lukashenko, who has been in power since 1994, has been cracking down on any form of dissent since mass protests erupted after last year's elections, deemed unfair by the West.

BBelarusian athlete Krystsina Tsimanouskaya said she was forced to withdraw from the Tokyo Olympics and threatened with forced repatriation
BBelarusian athlete Krystsina Tsimanouskaya said she was forced to withdraw from the Tokyo Olympics and threatened with forced repatriation AFP / Yuki IWAMURA

Many Belarusians have fled, often to neighbouring Ukraine, Poland and Lithuania.

"Vitaly Shishov, who had gone missing in Kiev yesterday, was today found hanged in one of the Kiev parks, not far from where he lived," the police said in a statement.

The United Nations and Washington called on the Ukrainian authorities to conduct a thorough investigation.

Belarus strongman Alexander Lukashenko has been cracking down on any form of dissent since mass protests erupted after last year's elections
Belarus strongman Alexander Lukashenko has been cracking down on any form of dissent since mass protests erupted after last year's elections AFP / Sergei SUPINSKY

UN human rights spokeswoman Marta Hurtado told reporters in Geneva that "the situation (in Belarus) is deteriorating clearly".

The US embassy in Kiev said the death came "amid an unacceptable Belarusian crackdown on civil society" and called on Ukraine to do a "complete and thorough investigation".

Police said Shishov was found hanged in a Kiev park not far from where he lived.
Police said Shishov was found hanged in a Kiev park not far from where he lived. AFP / Sergei SUPINSKY

In Washington, State Department spokesman Ned Price renewed a call "for an end to the crackdown, the immediate release of all political prisoners" and free elections.

Ukrainian police had earlier said a murder probe has been opened.

Igor Klymenko, head of the national police, told reporters that officers were pursuing two main leads: suicide and murder disguised as a suicide. He said the activist had scratches on his nose and body which were consistent with a fall.

Igor Klymenko, head of the national police, told reporters police were pursuing two main leads: suicide and murder disguised as a suicide.
Igor Klymenko, head of the national police, told reporters police were pursuing two main leads: suicide and murder disguised as a suicide. AFP / Genya SAVILOV

Several hundred people rallied outside the Belarus embassy in Kiev on Tuesday evening, many holding white and red flags associated with the Belarusian opposition.

Belarusian athlete Krystsina Tsimanouskaya said she was forced to withdraw from the Tokyo Olympics and threatened with forced repatriation
Belarusian athlete Krystsina Tsimanouskaya said she was forced to withdraw from the Tokyo Olympics and threatened with forced repatriation AFP / Yuki IWAMURA

The Belarusian House in Ukraine accused the Lukashenko regime of having murdered Shishov.

The head of the Belarusian House in Warsaw, Ales Zarembiuk, told AFP he was "100 percent convinced" that Shishov was murdered in a bid to frighten the Belarusian diaspora, whose organisations supported last year's protests.

According to Zarembiuk, Shishov ran an account on Telegram that exposed KGB agents.

Zarembiuk -- who said he never walks alone -- said Belarusians are less safe in Ukraine than in neighbouring Poland because of its ongoing war with pro-Russia separatists.

"He may not have been killed by a KGB agent, but it was definitely on their orders."

Belarus has a history of political killings and disappearances, and regime critics have claimed that the Belarusian security services run death squads that hunt down and target Lukashenko opponents.

Kiev has been accused of not properly investigating the killing of Belarusian journalist Pavel Sheremet in Kiev in 2016.

Ukrainian president Volodymyr Zelensky was "closely following the findings of the police", his spokesman Sergiy Nikiforov said.

Speaking after meeting UK Prime Minister Boris Johnson in London on Tuesday, exiled Belarusian opposition leader Svetlana Tikhanovskaya said Shishov's death was most likely due to criminal activity but she wanted to wait for the results of the police probe.

The head of the KGB security service, Ivan Tertel, said that Ukraine, Poland, and the Baltic states had US-backed "centres for information and psychological operations" which they used to "isolate" Minsk.

The sprinter, who was granted a humanitarian visa by Poland on Monday, said she feared being jailed if she returned to her country.