Nearly 100 Croatian soccer fans appeared in an Athens court Wednesday to face criminal charges that include murder and membership of a criminal organization over their alleged involvement in deadly fan violence.

The handcuffed youths -- many with their shirts pulled over their heads to hide their identity -- appeared before an investigative magistrate a day after a 29-year-old Greek fan was stabbed to death outside AEK Athens' stadium, prompting the cancellation of a Champions League qualifier against Dinamo Zagreb.

Court officials said the magistrate issued the blanket charges against all 103 suspects, including 97 Croatian nationals. The indictments also included charges of assault and illegal possession and use of explosive material. The murder-related charge is likely to be dropped for most of the defendants as the investigation proceeds.

Amateur video of the attack showed dozens of youths wielding bats and iron bars running past the stadium as flares and petrol bombs exploded. Ten people were injured and four remain hospitalized.

Elsewhere in Greece, police set up highway roadblocks and additional border checks to search for more suspects. Authorities announced that six Croatian nationals were arrested as they attempted to flee the country. Five of the suspects were detained in the northwestern port of Igoumenitsa as they prepared to board a ferry bound for Italy, while the sixth was arrested on a bus bound for Albania.

More violence was feared later Wednesday as Athens club Panathinaikos faced Marseille in a Champions League qualifier, which went ahead under strict security measures at Leoforos Stadium in the center of the Greek capital.

Police set up a cordon around the stadium and patrolled nearby intersections and subway stations.

By half-time no violence had been reported. Traveling French fans were not given tickets. State ERT television said three people were arrested outside the stadium for trying to carry in knives and flares.

The vice president of the European Commission, Greek politician Margaritis Schinas, condemned "the horrible violence" that occurred at AEK's stadium.

"[There is] no place for violence and hooliganism in European football," he wrote in an online post, adding that he had contacted the head of European soccer's governing body, UEFA President Aleksander Ceferin, to discuss the incident.

The Greek capital will also host the UEFA Super Cup next week between Manchester City and Sevilla in a showdown between the Champions and Europa League winners.

Greek Public Order Minister Giannis Oikonomou said the police had made "tragic errors" in failing to stop the traveling Croatian supporters and failing to act on information that clashes were likely. He dismissed calls from opposition parties to resign and suspended seven police officers, including several in senior positions, pending an investigation and their reassignment or dismissal.

Outside AEK's Opap Arena, fans set up tributes to the supporter who was killed -- identified by family members as Michalis Katsouris from a town near Athens -- leaving flowers and candles at the site where he died of a stab wound.

AEK called for UEFA to impose "immediate and severe punishment" on Dinamo Zagreb, expressing disappointment that the qualifier will go ahead in Zagreb later this month.

"The question that torments our fans is one that we described from the outset and that also torments us: How is it possible that following the brutal murder of Michalis by a gang of vicious criminals from Croatia, for AEK Athens to enter the field and play against this team?" AEK said.

"Will any of his killers be in the stands?"

The Croatian government and Dinamo have both strongly condemned the attacks in Athens. But the Zagreb club defended their actions, insisting they had fully cooperated with authorities, and rejected calls from AEK for expulsion from European competitions.

In a joint statement, meanwhile, the mayors of Athens and Zagreb, Kostas Bakoyannis and Tomislav Tomasevic appealed for calm.

"Athens and Zagreb maintain friendly ties, and as mayors we are committed to strengthening them," they wrote. "This senseless violence has no place in our stadiums, in our cities and in our societies."