Fifa has condemned the ticketless Chile fans who invaded the Maracana's media centre in the build-up to their team's Group B crunch clash with Spain on Wednesday.
Dozens of supporters broke through a security gate and smashed through the doors to the centre before pulling down a temporary partition wall in a bid to reach the stands.
Stewards and security officials eventually pinned down the group in a corridor next to the media centre and held them there for a short time before leading them to police.
Fifa insists none of the supporters managed to reach the stands and says such "violent" acts will not be tolerated.
"Ahead of the Spain-Chile match at the Maracana, a group of individuals without tickets violently forced entry into the stadium," a statement issued on Twitter read.
"They broke fences and overran security before being contained by security. They did not make it to the seats.
"The situation was brought under control quickly and at least 85 intruders were detained by the military police of Rio.
"The organisers of the World Cup condemn these acts of violence. We’ll communicate further info and measures to be taken in due course."
This latest incident constitutes the second security breach at the Maracana inside a week and raises serious questions about the capability of Fifa and Rio authorities to maintain safety at next month's World Cup final.
On Sunday around 30 ticketless Argentina supporters scaled an outer wall and broke through a gate before being detained prior to their team's Group F opener with Bosnia-Herzegovina.