Rome is on red alert with 3,000 police officers deployed to avoid ugly scenes during Roma's Champions League return leg match against Liverpool at the Stadio Olimpico on Wednesday.
Liverpool supporter Sean Cox, a 53-year-old Irishman, remains in critical condition after being attacked close to Anfield by visiting supporters before last week's semi-final, first leg.
Around 5,000 Liverpool fans are expected to attend and authorities fear rival gangs could clash from Tuesday evening when many Reds fans begin arriving in the Italian capital.
British police are in Rome backing up their Italian counterparts with city authorities saying 1,000 officers are being deployed around the Stadio Olimpico in addition to a further 2,000 throughout the city.
Furthermore, there will be a complete alcohol ban, as well as a huge crackdown on fake tickets.
Merseyside Police Chief Superintendent Dave Charnock urged fans not to travel to Rome without tickets.
"If the details on your ticket and passport do not match, you will be refused entry to the ground by Italian authorities," said Charnock.
Liverpool fans have been warned to use shuttle buses and not to leave the Stadio Olimpico on foot.
"Under no circumstances should supporters attempt to walk," the club warned.
- 'Stab city' -
The club have also told fans to respect public monuments in the capital, to avoid street drinking which is prohibited, and stay clear of the Ponte Milvio and Ponte Duca d'Aoste, two bridges near the stadium.
Fans have also been told to avoid areas of the north of the city on match day, and to expect a long wait before being allowed to leave the stadium.
Liverpool manager Jurgen Klopp and Roma counterpart Eusebio Di Francesco both appealed for calm along with club legends Francesco Totti and Robbie Fowler.
Wearing the colours of the Irish flag, Klopp said: "The game on Tuesday night showed the beauty of the game, and it showed the most ugly face of parts of the game.
"What can I say? Behave? It's easy to say!"
"I've already said that I stand shoulder-to-shoulder with Sean Cox and his family and I'm against all forms of violence, like we all are here," said Di Francesco.
"Every set of supporters has some bad apples, who do things that they shouldn't. All over the world, unfortunately, there are those who ruin great evenings like the first leg.
"I hope it's an enjoyable occasion for those coming to the stadium tomorrow, that's what I’m pleading for."
But the bad blood between Roma and English fans goes back decades.
Liverpool's last visit in 2001 was blighted by missile attacks inside the stadium and stabbings.
English fans who visited for the 1984 European Cup final -- where Liverpool famously beat Roma on penalties -- dubbed the Italian capital 'stab city'.
Middlesbrough fans were also the victims of stabbing attacks in 2006, while there was trouble the following year with Manchester United supporters.
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