Zivkovic appeared to backtrack in his comments to BIRN, saying he had returned to Donbass to help child victims of mines.

Asked about his YouTube video, Zivkovic replied: “Everyone fights in their own way – some with a gun, some with propaganda, some with other acts,” he said.

Zivkovic nevertheless criticised the 2014 Serbian law that forbids Serbian citizens from participating in foreign wars.

“I will always laugh at it,” he said, “until it clearly makes a difference between volunteers and mercenaries.” Zivkovic denied being paid for his involvement in the war.

Bojan Elek, a researcher at the Belgrade Centre for Security Policy, a think-tank, questioned the prosecution’s decision not to investigate Zivkovic as an active fighter in the war.

“So far, the prosecution based indictments on the fact Serbian citizens were fighting in Ukraine, so it is not clear why this time was different,” Elek said.

“This is a clear indication of the lack of commitment of authorities in Serbia to solve the problem of foreign fighters on the Russian side in Ukraine.”

In its reply to BIRN, the Serbian Justice Ministry said that it had not received any request for the extradition of Zivkovic.

Investigated in Ukraine, banned by Bosnia, Montenegro and Romania

Zivkovic regularly posted pictures on Facebook showing him in Donbass with soldiers of the self-proclaimed ‘Donetsk People’s Republic.’ He was also pictured with Igor Strelkov, a Russian former militant commander in eastern Ukraine.

In June 2018, Radio Free Europe reported that Zivkovic was one of six Serbian citizens – among a total of 54 foreigners – under investigation in Ukraine for membership of “illegal armed formations”. BIRN was unable to ascertain the status of the probe.

Zivkovic was banned from Montenegro in 2015. In 2017, he was expelled from Romania and given a 15-year entry ban after authorities accused him of spying on NATO military bases in the country’s southeast and showing an interest in obtaining classified information on military installations.

He is also banned from Bosnia, where he was named in the country’s first indictment against a Bosnian citizen for fighting in Ukraine. The accused, Gavrilo Stevic, is due to appear in court for a plea hearing on June 17.

According to the indictment, seen by BIRN, Stevic told prosecutors he had contacted the Serbian nationalist movement that Zivkovic leads, ‘Ravnogorski Pokret’ and which Stevic said “organised volunteer trips”.

He said Zivkovic had called him in July 2014 to travel to Belgrade, where he was introduced to a group of volunteers and with whom he left for Russia and then Ukraine. Stevic said he had planned to work there as a journalist but was encouraged by Zivkovic to fight under his command.

Describing Stevic as a “great friend and brother”, Zivkovic said he could not comment on an ongoing investigation.

Zivkovic said he would not hide his readiness “to help every Serb who comes here.”

“None will be hungry or thirsty,” he said. “But I’m not mustering anyone or organising anything for anyone.”

Note: This article was updated at 2:30pm on June 14 to include a statement by the Serbian Justice Ministry.