Poland's sports minister said on Thursday she was disappointed by the lenient sentences handed out so far to the hooligans who attacked Russia supporters on their way to the stadium for a match with the Euro 2012 co-hosts earlier this week.
On Wednesday a Warsaw court handed out the first sentences to hooligans who took part in the bloody skirmishes with Russian supporters that resulted in police detaining 184 people, 156 of them Poles and most of the rest Russians.
Two perpetrators have been sentenced to three and five months in jail, while four others received suspended jail terms of up to 12 months and one a 500 zloty ($150) fine, a spokesman for one of the courts dealing with the cases said.
The district court for central Warsaw had so far scheduled 37 cases for Thursday, but could see as many as 90, he added.
Polish officials have apologised for the incidents and called for harsh punishment.
"We cannot influence the justice system. But in my opinion the punishment should be more severe," Sports Minister Joanna Mucha told a news conference.
"It's important to create an atmosphere where there's no permission for these kinds of situations."
Russian President Vladimir Putin told Poland's Prime Minister Donald Tusk during a phone conversation on Wednesday that Warsaw bore "full responsibility" for the safety of fans, comments raising the stakes in a violent confrontation which brought the nations' troubled relationship to the fore.
The trigger for Tuesday's violence was a march across Poniatowski bridge in central Warsaw by thousands of Russian fans to commemorate Russia's Independence Day.
Police were pelted with missiles and responded by firing tear gas and rubber bullets at masked youths.
Poland expects 20,000 Russian fans to arrive in Warsaw with tickets for the final Group A match with Greece on Saturday, twice the number who came to the game with Poland on Tuesday.
"We are doing everything to assure a really high level of safety and prevent any incidents of this kind," Mucha said.