Brasilia: Some 200 Chilean soccer fans stormed the Maracana media centre around an hour before kick-off in the World Cup match against Spain on Wednesday, raising major concerns for FIFA and tournament organisers.
The fans charged through a security checkpoint before smashing down a glass door, witnesses said, and invading the working room.
They ran around the journalists` workplace looking for access to the stadium, before police were called.
A group of 30 were being held by security while others ran away.
"They stormed the gate and ran into the stadium. We stopped them," security guard Diego Guilhermede Souza Goncalves told Reuters.
The spectators were being held seated on the floor, while police took them away in groups.
"A group of individuals without tickets violently forced entry into the stadium, breaking fences and overrunning security," world soccer`s governing body FIFA said.
"They were contained by the security and did not make it to the seats. The situation was brought under control quickly and at least 85 intruders were detained according to the military policy of Rio.
"The organisers of the FIFA World Cup condemn these acts of violence and we will communicate further information and measures to be taken in due course."
At least one Chilean fan, a woman, was injured and taken outside in a wheelchair.
There had been a lively atmosphere around the Maracana earlier on Wednesday, with thousands of red-shirted fans singing, chanting and dancing in the streets.
One group wearing wigs and sporting face-paint were drinking from a red wine bottle at 10 o`clock in the morning.
Chilean fans in the stadium were in high spirits too, singing loudly and drowning out Spanish supporters as the players jogged out to warm up.
Chile, who won their opening group match against Australia 3-1, have high hopes for Wednesday`s Group B game against world champions who were thumped 5-1 by the Netherlands in their opener.