Mourners spilled over into a square outside the church on what would have been Mikhail Zhiznevsky’s 26th birthday, many bringing flowers and waving Ukrainian flags with black ribbons.

All three chief opposition leaders — boxing champion Vitali Klitschko, former minister Arseniy Yatsenyuk and nationalist Oleg Tyagnybok — attended.

Some red and white nationalist flags from before Belarus became a Soviet republic — currently banned by the country’s authoritarian regime — were also seen at the ceremony.

“He was a very brave, very kind person who gave his life for the future of Ukraine,” Iryna Davydova, a Kiev resident paying her respects, told AFP.

“Just the fact that so many people who did not know him have come to bid farewell means that he, a Belarussian, has become a Ukrainian hero,” she said.

Yuriy, a friend of Zhiznevsky who asked that his surname not be used, said he was sceptical that those guilty of his shooting would ever be punished.

Ukrainian officials have confirmed Zhiznevsky died of gunshot wounds, but security forces have denied shooting on protesters.

“It’s a shame when people like him leave us,” said Yuriy, explaining Zhiznevsky had been one of the protesters assigned with ensuring security at the protest camp.

“He took the injured away from clashes,” he said, adding that Zhiznevsky had been living in Ukraine for several years.

“On Independence Square he was responsible for law and order, he ensured people’s security, took away the injured from the clashes,” he said.

“This was an intentional killing, not accidental. We do not believe they will find the guilty,” he said.

Zhiznevsky’s body is due to be flown to Belarus for burial later Sunday.