PARIS (AP) - In a season when soccer violence has made an ugly comeback, a potential menace hangs over Wednesday's Europa Conference League final between Dutch club Feyenoord and Italy's Roma in the Albanian capital of Tirana.
Up to 100,000 fans are expected to travel despite each club being allocated only 4,000 tickets for the inaugural final of the third-tier European tournament, which was designed to give smaller clubs a shot at a continental competition.
Feyenoord and Roma are storied clubs with big fan bases, and notorious violent elements among their support.
The final is set to be played just days after a weekend of violence at games capped a season-long resurgence of it.
Fighting and tear gas marred the Greek Cup final on Saturday, with a player allegedly hit by a chunk of cement thrown from the crowd during Panathinaikos' 1-0 win over PAOK Thessaloniki.
In Croatia, police and Hajduk Split fans clashed on a major highway later Saturday. The violence escalated when a convoy of more than 260 cars and buses was transporting Hajduk Split fans under police escort after their team lost 3-1 to Dinamo Zagreb. Split's Torcida Ultras had earlier clashed with bitter rivals from Zagreb's Bad Blue Boys group.
On Sunday, Manchester City issued an apology for what it described as an assault on Aston Villa goalkeeper Robin Olsen during a field invasion by City fans celebrating the club's Premier League title.
Elsewhere, supporters of from Italian clubs La Spezia and Napoli fought with sticks in the stadium and then continued in the streets and, in Bosnia and Herzegovina, some Rudar Prijedor fans attacked their own players after a 5-2 defeat.
The violence has been escalating, perhaps because of frustration unleashed following the end of lockdown restrictions imposed during the COVID-19 pandemic.
Hooligans from Feyenoord were reportedly among those who clashed heavily with police in Rotterdam during a November riot against coronavirus restrictions.
There have been numerous pitch invasions and fights inside stadiums in countries such as Switzerland, the Netherlands and Slovakia.
Last September, the Europa League game between Marseille and Turkish club Galatasaray was interrupted after rival fans threw flares and firecrackers at each other. Rival fans fought inside Stade Velodrome after fulltime and Marseille supporters then clashed outside with police.
In January, England's football policing lead Mark Roberts said arrests across the top five English leagues were the highest in years. An alarming increase in recent pitch invasions culminated with a Premier League coach kicking a fan as he was goaded when trying to cross the field.
In February, Greek authorities promised to toughen rules governing supporters' associations in the wake of a fatal attack involving a 19-year-old man who was attacked by a gang of youths in Thessaloniki.
Two months later, PAOK played in Marseille, where local supporters confronted PAOK's Ultras outside their hotel on the eve of the match. PAOK supporters clashed violently with riot police and rival fans threw projectiles and flares at each other throughout the game.
More disorder followed three weeks ago, when hundreds of Feyenoord supporters were involved in frenzied brawls with their Marseille counterparts before the return leg of their semifinal encounter.
Marseille supporters even praised Feyenoord on a Twitter forum for arriving without any police protection, and one of Feyenoord's hooligan groups described the events with twisted humor.
"Two fantastic days and nights in Marseille," the post read. "Attacks can be expected from many corners of the streets. A very recommendable city for a good away day."
Many Feyenoord fans arrived without tickets in Marseille for the May 5 match, making it harder to police. There were clashes in Germany the same night at the Europa League semifinal between Eintracht Frankfurt and West Ham.
Violence often occurs the night before matches, when there's less police around, then continues as more fans arrive. On May 18, there were shocking scenes in Sevilla's city center when Frankfurt took on Scottish club Rangers.
Several hundred Frankfurt fans attacked a few dozen Rangers supporters outside a bar.
Frankfurt's attack breached codes observed by ultras and hooligans themselves, where violent fans are supposed to only fight each other.
In this respect, Rome's clubs have gained an unpopular reputation. Non-aggressive fans have been attacked during games at Roma and Lazio. Some were stabbed.
There is also potential bad blood with Feyenoord after events in Rome in 2015, when Feyenoord fans clashed with Italian police and damaged an historic fountain.
Roma's hardcore Ultras number around 200 and Feyenoord's hooligans seemingly have set their sights on them, with a cartoon posted on a social media forum appearing to show intent.
The drawing depicted a boat landing on shore with 1908 written on the side of it - the year the Rotterdam-based club was created - and with bloodied Roman legionaries cowering behind their shields.
Roma's Ultras warned fellow supporters to behave in Tirana by placing a note on seats before the team's last Serie A home match against Venezia.
"We have an appointment with History and we've got to be respectable. The trip to Tirana should be dealt with fairly inside and outside the stadium," it read.
LOCAL THREATS AND SECURITY
Adding to tensions between Feyenoord and Roma is the fact that Tirana has supporter groups from local clubs Dinamo and Partizani, who potentially could seek out either or both.
Given the threat to Roma's Ultras, from Feyenoord and possibly Tirana's groups, they could find themselves outnumbered and may have support from other Ultras.
Alliances between Ultras groups from different countries and clubs have tightened. For instance, when West Ham clashed with Frankfurt they were backed up by some Ultras from Lazio.
UEFA, European football's governing body, the Albanian soccer federation and law enforcement authorities have taken precautions ahead of Wednesday's final. There will be 650 stewards inside the stadium and at least 2,700 Tirana-based police officers.
"We shall take measures to prevent any act of violence or any instigator of violence so that (the situation) does not degrade," Albanian Interior Minister Bledi Cuci said. "We have undertaken all the measures to prevent such a thing."
Andrew Dampf in Rome, Llazar Semini in Tirana, Albania and Graham Dunbar in Geneva contributed.
More AP soccer: https://apnews.com/hub/soccer and https://twitter.com/AP_Sports