Tunisian fans riots during Esperance game against Qatari side Al Sadd in the FIFA Club World Cup
Several fans from the African champions attempted to get on the pitch at the final whistle after the side from Tunis were defeated 2-1 on Sunday, and one Esperance supporter made it to within feet of players and officials.
That an angry fan was able to leap a barrier, evade security and get so close will come as an embarrassment to FIFA, the world governing body, in what is one of its most high-profile tournaments of the year.
Police wrestled to the ground several Esperance fans who tried to get onto the pitch, further riling fans who were already irate at what they perceived to be several key decisions that had gone against the Africans.
"Following disturbances at the conclusion of yesterday's match between Al Sadd and Esperance, the security forces inside the stadium acted as quickly as possible to restore order," FIFA said in a statement on Monday.
Blaming a "minority of supporters", it said FIFA would increase security for Esperance's match against Monterrey of Mexico on Wednesday to decide who finishes the annual intercontinental tournament fifth.
Esperance fans, some of whom appeared to be drunk, had confronted supporters of the CONCACAF champions outside the Toyota Stadium on Sunday, Mexican journalists at the scene said.
Monterrey later crashed to Japanese champions Kashiwa Reysol on penalties.
FIFA, which said nobody was injured or arrested in the trouble after the game with Asian champions Al Sadd, could also punish Esperance for the behaviour of its fans, several hundred of whom were at the match.
Nabil Maaloul, the coach of African Champions League winners Esperance, who are known as "the blood and gold" because of the colour of their kit, apologised afterwards.
"I'm really sorry. Sometimes that happens. Tunisia and Al Sadd are sisters, but of course this should not happen," he said.
The Tunisian fans and players were furious after Chilean referee Enrique Osses ruled out two goals for offside and failed to award them what looked like a penalty in the dying minutes.
Football hooliganism is extremely rare in Japan, but police and stewards were forced to intervene on at least two sides of the stadium in Toyota, where Esperance were cheered on by a small but vociferous minority of mostly men.
The disturbances cap a difficult year for FIFA and its controversial president Sepp Blatter.
The Swiss apologised last month after he said allegations of on-pitch racism should be settled by a handshake, leading to calls for his resignation. British Prime Minister David Cameron labelled the comments "appalling".
FIFA this year also launched an anti-corruption drive to bring transparency to the powerful world body.
The Zurich-based organisation has been mired in corruption allegations since June over Blatter's acrimonious battle for the FIFA presidency with Asian football supremo Mohamed bin Hammam.
The Qatari was eventually banned for life from all football-related activity after being accused of trying to buy votes in the bitter election fight.
He has constantly denied the allegations and vowed to clear his name.
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