Fences have been breached by fans at both World Cup matches staged at the country's biggest and most prestigious stadium which hosts the final on July 13.
"It is embarrassing," FIFA director of security Ralf Mutschke said Thursday, one day after 88 ticketless Chile fans broke into the sold-out venue ahead of their team's 2-0 win against Spain.
Mutschke said security operations at the World Cup must "improve in order that this will not happen again."
Brazilian authorities said the fans were detained after smashing their way through a perimeter wire fence into the stadium media centre.
Fans stampeded through the media working area, knocking down partition walls while trying to gain access to the pitch area. They were detained by some of the 1,000-plus private security officers on match duty.
"We have to protect the media, there's no doubt about it — we also have to protect the (other) fans," Mutschke said at a news briefing to address the incident.
Chile's consul general in Rio, Samuel Ossa, told reporters that the fans will be arrested if they do not leave Brazil within 72 hours and would likely have to spend time in jail while Brazilian authorities go through a process to deport them. The total number of those detained and released was 90 because a Bolivian and a Colombian were with the group of Chileans, he said.
"They're getting off easy," Ossa said. "They were not criminals. They are people who overstepped their passion and made a mistake and have to pay for it."
But the president of Chile's football federation — which could be disciplined by FIFA over the incident — said the Chileans fans who invaded the stadium could face sanctions after they get home.
"The large majority of Chilean fans show excellent, exemplary behaviour that was marred by ... so-called fans," Sergio Jadue said Thursday at the team's training camp near Belo Horizonte. "We don't want these kinds of people at our fields."
Four days earlier, at least 10 Argentina fans were detained in Rio after jumping fences to try to see their team play last Sunday in another sold-out match against Bosnia-Herzegovina.
Chilean fan Luis Galvez said his group of friends without tickets got past four security lines until being stopped outside the stadium.
"There were a lot of rumours going around that it was easy to get in," said Galvez, a 29-year-old physical therapist. He described the break-in as an embarrassment.
"It's one thing to try and get in without a ticket and quite another to get in a fight with security and start destroying things," he said.
FIFA and the local organizing committee plan to announce improved security measures Friday.
"Operational procedures are being reassessed and definitely you will see a difference in the next event," Hilario Medeiros, security manager for Brazilian organizers, said through a translator.
The Maracana hosts Belgium vs. Russia on Sunday, the third of seven matches there.
Security issues have been an issue at other World Cup venues, with stadium staff failing to arrive for work in Brasilia last Sunday and on Tuesday in Fortaleza, where Brazil played Mexico.
Medeiros said the Maracana was fully staffed Wednesday with 1,037 security workers.
"We knew that this was a high risk operation," Medeiros said.
Mutschke said other aspects of the security plan worked well at the airport-style security checks.
"There was a lot of butterfly knives seized by 'mag and bag.' There was tables full of pyrotechnics and firecrackers," Mutschke said. "The stewards did a good job despite the incident."
Associated Press writers Joshua Goodman, Jorge Sainz and Pablo Giusanni in Rio de Janeiro and Belo Horizonte, Brazil contributed to this report.