A brutal attack on fans of English football club Tottenham Hotspur in Rome has stoked fears in Italy of rising right-wing and anti-Semitic violence.
Italy's capital has been rattled by increasing militancy by the extreme right since October, with weekly demonstrations by the neo-fascist youth group Blocco Studentesco often ending in clashes with police.
Local media initially blamed Thursday's attack on hard-core fans or 'ultras' supporting Lazio, who Tottenham had travelled to the capital to play in the Europa League.
But two supporters of AS Roma, Lazio's bitter city rivals, were among the 15 detained for alleged involvement in the mass attack on a downtown bar, suggesting a possibly different motivation.
Tottenham have a large contingent of Jewish fans and witnesses told Italian media that masked men armed with knives and baseball bats shouted "Jews, Jews"