Protesters in the Ukrainian city of Odessa have barricaded the city hall, Ukrainian news website 112.ua reported Tuesday.
Crowds calling for the resignation of city mayor Gennadiy Trukhanov blocked entrances to the building with trash cans, tires and fences, according to media reports.
The protest was triggered after a peaceful picket was attacked in the early hours of Tuesday morning, Ukrainian news outlet Liga.net reported.
Up to 40 men armed with baseball bats arrived at the picket in a minibus at around 4 a.m., Odessa regional administration official Alexander Borovik wrote on Facebook.
CCTV in the area was turned off at the time and did not capture the men beating protesters.
Local authorities reported that five of the attackers were arrested by police, Liga.net said.
Protestors had been picketing outside the government building since April 10 following allegations of Trukhanov's involvement in the Panama Papers scandal.
Leaked information allegedly showed that the Odessa mayor had identified himself as a Russian citizen in more than 20 offshore holdings, Ukrainian news website hromadske.tv reported.
“It's unlikely that the mayor will resign,” said Ukrainian journalist Katya Sergatskova.
“It was a small group of activists who were attacked. There is a possibility that protests in the city could increase, but we will have to wait and see. Kiev still hasn't reacted to the incident.”
Trukhanov has denied holding a Russian passport, which is an offense under Ukrainian law, the Meduza news website reported. Dual citizenship of any kind is not recognized in Ukraine.