World Cup 2018: Fifa president Gianni Infantino 'not concerned' about hooligan threat at Russia World Cup
Fifa president Gianni Infantino says he is "not at all concerned" by the threat of hooliganism at next year's World Cup in Russia.
At Euro 2016, there were violent clashes between Russian and English supporters in Marseille.
One Russian fan, speaking as part of a BBC documentary to be broadcast on Thursday, said trouble is "100% guaranteed" at the 2018 World Cup.
Infantino also said the 2026 event could be hosted by multiple countries.
The president said he has "full confidence" in the Russian authorities to combat any trouble next summer, adding they are taking the matter "very seriously."
He also said World Cup organisers were already putting in place plans to prevent any trouble at next summer's World Cup and would "learn" from the problems at Euro 2016.
"They have been in contact with Uefa and French organisers to learn the lessons from France," he said.
"As part of this, the Russian government has put in place an ID system which will help us when it comes to any potential trouble."
Watch Russia's Hooligan Army, BBC Two, Thursday 16 February at 21:00 GMT.
Multiple host nations
Infantino said the host countries for the 2026 World Cup, would "ideally" be close to one another for "the ease of travel".
Football's world governing body agreed in January on a 48-team competition in 2026. The bidding process has not begun yet for the tournament.
"It is perfectly in line with our sustainability and legacy to maybe bring together two, three, four countries who can jointly present a project with three, four, five stadiums each," said Infantino, speaking during a visit to Qatar on Thursday.
The next European Championship, to be held in 2020, is being hosted across 13 cities.
Qatar is hosting the 2022 World Cup and is spending almost $500m (£400m) a week on major infrastructure projects in preparation.
Infantino says he is confident the stadiums and infrastructure will be ready in time, but added "a lot remains to be done".
BBC Radio 5 live sports news correspondent Richard Conway
Bidding for the 2026 World Cup is likely to begin later this year.
It will be an expanded tournament, featuring 48 teams.
Infantino says he wants to encourage three or even four countries to group together to stage games.
This, he feels, would be in line with ensuring the World Cup is sustainable - a criticism Fifa often faces given the huge costs single countries must foot to stage the event.
The USA is the early favourite to win the 2026 bid but co-hosting with Canada and even Mexico, despite the current political and border difficulties with the Trump administration, now looks a real possibility.
The move is also politically astute for Mr Infantino, who will likely stand for re-election as Fifa's leader in 2019.
Many smaller nations will welcome the opportunity to stage at least part of the sport's premier competition, something he hopes they will remember come polling day.