FIFA is investigating a possible racial discrimination case after photographs circulated of fans with blackface makeup at Germany's match against Ghana.
Images posted on social media networks showed two men, appearing to be Germany fans, with blackened faces in the Fortaleza stadium on Saturday.
FIFA says its disciplinary committee is considering opening a case.
FIFA spokeswoman Delia Fischer says "we do not respect any discriminatory messages."
FIFA holds national football federations responsible for their fans' behavior inside stadiums.
In a second incident, a man ran onto the pitch in the second half of the 2-2 draw.
The shirtless fan had an email address and telephone number written on his back.
Brazil's organizing committee spokesman Saint-Clair Milesi says the man, reportedly from Poland, was detained by local authorities.