Sao Paulo Grand Prix organisers recognised safety failures and committed to fix them for next year after spectators invaded the track before the end of Sunday's Formula One race.
Stewards said in a statement that a large group of spectators had accessed the run off area at turn one while cars were still on the track.
The Sao Paulo F1 Organisation (SPF1) had "candidly admitted the failures in terms of the security protocols and safety measures", they added.
"SPF1 stated, in mitigation, that they would conduct a thorough investigation and take steps to remediate in time for the next event in Brazil."
The stewards ordered organisers to present the formal remediation plan to the governing FIA by the end of next January.
The matter was also referred to the FIA's World Motor Sports Council for "a further investigation to determine whether any additional steps need to be taken or penalties applied beyond the remediation plan."
The Brazilian circuit is one of the most atmospheric on the calendar and track invasions after the race have become common, even with no Brazilian drivers.
Red Bull's Max Verstappen won on Sunday for the 17th time this season.
Formula One announced earlier in the week that it had extended the contract for Sao Paulo to host the Brazilian race until 2030, a five-year extension as the current contract had been due to expire in 2025.
"I can't wait for many more years of the wonderful atmosphere that the Brazilian fans bring," F1 chief executive Stefano Domenicali said at the announcement. "This iconic circuit is a favourite of drivers and fans."