Russia accused Polish soccer fans on Wednesday of provoking street battles with Russian supporters on the night of their countries' Euro 2012 match and urged Warsaw to prevent further clashes in the tournament.
Russian President Vladimir Putin also told Poland's leader Warsaw bore "full responsibility" for the safety of fans, the Kremlin said - comments during a phone conversation which raised the stakes in the violent confrontation which brought the nations' troubled relationship to the fore.
Fighting erupted as thousands of Russian fans marched towards the stadium before the match on Tuesday, which ended in a 1-1 draw. Masked hooligans attacked Russian fans. Some Russians fought back and both groups also clashed with police.
Polish authorities apologized on Wednesday for the tournament's first significant outbreak of violence but Prime Minister Donald Tusk played down its scale and significance.
"It wasn't a Poland-Russian battle on the streets of Warsaw," Tusk said. "Only a few hundred idiots tried to prove they are more important than the fans or the whole tournament. I would leave politics out of this."
Russia's foreign ministry said there had been efforts to protect Russian fans in Warsaw. "But unfortunately, provocations by some groups of Polish fans could not be avoided," Russian foreign ministry spokeswoman Maria Zakharova said in a statement.
"We truly hope that the events of June 12 are not repeated, that the Polish authorities take all necessary measures and that the remaining matches are a true celebration for all lovers of soccer," the statement said.
Putin called Tusk on Wednesday to express his concern about the violence, the Kremlin said.
"Putin stressed that organizers of such international tournaments bear full responsibility for the safety of fans from other countries on their territory," Putin's spokesman Dmitry Peskov told reporters.
Tusk's office said the premier also discussed economic issues with Putin.
"Prime Minister Tusk expressed his belief that (the soccer clashes) should not have any influence on the good relations between the two countries," his office said in a statement.
The clashes were an embarrassment for Poland which had until Tuesday presided over a mostly peaceful tournament with co-host Ukraine.
During an afternoon and night of skirmishes, police said they detained 184 people, 156 of them Poles and most of the rest Russians.
Many Poles still resent decades of Soviet domination after World War Two and the increasingly nationalistic tone of the rhetoric from Moscow.
"We are very sorry that our guests were attacked by hooligans and they lost their feeling of security," said Jacek Kozlowski, Governor of Masuria province which includes Warsaw.
Poland's Interior Minister Jacek Cichocki said he hoped courts would issue stiff sentences on Polish troublemakers, and Russian culprits would likely be expelled and banned from entering Europe's border-free Schengen area for five years.
UEFA, the European soccer's governing body that oversees the tournament, condemned the "isolated incidents" by "known troublemakers".
UEFA also said Russia would be docked six points in qualifying for the next European Championship if their fans step out of line again after disturbances at their opening Euro 2012 game against the Czech Republic last Friday.
Warsaw hosts a match between Russia and Greece on Saturday.
(Additional reporting by Justin Palmer and Lidia Kelly in Moscow and; Alexandra Hudson and Chris Borowski in Warsaw; Editing by Andrew Heavens)