Ukrainian tycoon Viktor Medvedchuk, captured by the country's special services after fleeing home arrest when Russia invaded, is seen as President Vladimir Putin's top ally in Kyiv who has been defending the Kremlin's interests for years.

In a picture posted online Tuesday by Ukraine's President Volodymyr Zelensky hailing the arrest, the lawmaker appeared a shadow of the super-rich powerbroker once dubbed the "dark prince" of Ukrainian politics.

Looking dishevelled with a messy mop of grey hair, the 67-year-old stared meekly into the camera with his hands in cuffs and wearing a rumpled Ukrainian army uniform.

News of the capture of Medvedchuk -- listed by Forbes last year as Ukraine's 12th richest person -- immediately sparked a celebratory outburst among Ukrainians online as they revelled in the comeuppance of man widely reviled for his close links to the Kremlin.

"It is a symbolic event, like capturing Goebbels, a great success from a moral and political point of view," said Sergiy Leshchenko, an advisor to Ukraine's presidency, referring to the Nazi propaganda chief.

"This is the man who was receiving direct instructions and resources from Putin to prepare the terrain for the invasion," he alleged.

Medvedchuk and the Kremlin deny that he has been pulling the strings for the Kremlin in Kyiv, but the businessman makes no secret of his proximity to Putin.

The ties between the two men date back to the early 2000s and Medvedchuk says the Russian leader is godfather to his youngest daughter Darya.

Medvedchuk and Putin were regularly photographed together at lavish events including the Formula 1 race in Sochi.

"We have a great relationship. It has been built over many years," he said in an interview with AFP back in 2019.

The authorities in Kyiv certainly believe that Medvedchuk remains a key Kremlin asset.

Security chief Ivan Bakanov said Wednesday that Russia's FSB intelligence agency was looking to spirit him out of Ukraine.

And Zelensky suggested swapping Medvedchuk for captured Ukrainian soldiers -- although the idea was dismissed by Moscow.

Medvedchuk was regularly photographed with Putin at lavish events
Medvedchuk was regularly photographed with Putin at lavish events AFP / STRINGER

Medvedchuk, a former lawyer, was long at the centre of Ukraine's murky nexus between money and politics.

Chief of staff to the country's second president Leonid Kuchma, he was accused of playing a key role in attempts to rig a 2004 vote in favour of pro-Russian candidate Viktor Yanukovych.

That election sparked a first uprising known as the Orange Revolution that foreshadowed the later Maidan revolution that shifted Ukraine towards the West in 2014 and ousted Yanukovych from power.

Medvedchuk continued to operate from the shadows during the turbulence rocking his homeland as Moscow responded by seizing the Crimea peninsula and igniting a war in eastern Ukraine.

He was sanctioned by the US for undermining the government and was involved in peace talks and negotiations for prisoner exchanges as a go-between.

Eventually, he bounced back to the centre of the political stage.

At 2019 parliamentary elections he headed the Moscow-backed Opposition Platform-For Life party as it came second behind Zelensky's bloc.

But Medvedchuk's fortunes began to deteriorate in February 2021.

Zelensky banned three pro-Russian television channels he was tied to and the authorities then seized his family's assets including a pipeline transporting Russian oil to Europe.

In May of that year he was charged with "high treason" over accusations of attempting to steal assets from Russia-annexed Crimea and later also for trying to buy coal from separatist-held regions.

He denied the allegations but was placed under house arrest.

Putin denounced the crackdown against him as a "political" purge and vowed to "respond".

"Medvedchuk was Putin's deputy, his most trusted man, his eyes and ears in Ukraine, who broadcast messages from Moscow" through his media, Leshchenko said.

Medvedchuk and the Kremlin have denied that he pulled strings for the Kremlin in Kyiv
Medvedchuk and the Kremlin have denied that he pulled strings for the Kremlin in Kyiv SPUTNIK via AFP / Mikhail KLIMENTYEV

As fears mounted of a Russian invasion, the US in January accused Medvedchuk of involvement in efforts by Russian intelligence services to prepare friendly Ukrainian politicians to take control of the country with the backing of occupying forces.

A few days after Russian troops rolled across the border, Ukrainian police announced Medvedchuk was missing after officers failed to find him during a check of his lavish home near Kyiv.

In the wake of his escape, Ukrainian media discovered on land at his residence a large train carriage decorated with gold and velvet and the Russian coat of arms, apparently a birthday present from his wife, TV presenter Oksana Marchenko, who fled to Russia.

neo-ant/del/har