Publishedduration1 hour agoimage copyrightReutersimage captionProtesters gathered outside Carrefours in Brazil to protest against the killing

The brutal killing of a black man at the hands of two white security guards outside a supermarket has sparked outrage across Brazil.

The killing happened on Thursday, the eve of Black Consciousness Day, and spurred anti-racism protests on Friday.

Footage showed Joao Alberto Silveira Freitas, 40, being repeatedly punched in the face by the guards at a Carrefour store in Porto Alegre.

One of the guards, it has emerged, was an off-duty military police officer.

They were arrested, and the Brazilian subsidiary of the French supermarket group Carrefour said it had cut ties with the security firm that provided the guards.