The Football Association is to report alleged incidents of anti-Semitic chanting by Lazio fans directed at Tottenham Hotspur to UEFA.
It followed a group of Spurs fans being attacked by a masked gang in a bar, leaving one man in a serious condition in hospital after being stabbed in the head and leg.
Lazio supporters displayed a 'Free Palestine' banner while some also sang Juden Tottenham towards the Jewish fans of the North London club in Thursday's night's Europa League match in Rome.
Now the FA has confirmed a complaint will be lodged with European football's governing body.
An FA spokesperson said: "We were saddened and alarmed to see reports of violent incidents prior to the game as well as anti-Semitic chants. The FA had a crowd control advisor present at the fixture who will provide an urgent report which we will pass on to UEFA as a matter of priority.''
On Friday, further developments emerged regarding the attack on Tottenham fans in Rome as the only two hooligans to have been arrested were revealed to be supporters of Roma rather than Lazio.
UEFA fined Lazio £32,500 for their fans' monkey chanting at three Spurs players during the reverse fixture in September.
Spurs boss Andre Villas-Boas has urged UEFA to take action if their fans are found guilty.
"It will take another investigation," Villas-Boas said. "It happened last time and it was acted upon quickly by UEFA. We will have to wait and see if there is anything to act upon. If there is UEFA have to act."
Information from Press Association was used in this report.