Motorists were advised to use alternative routes.
Rea Vaya bus services said Ellis Park buses remain diverted and the Fashion Square North station remained closed.
Police spokesperson Xoli Mbele could not immediately comment, saying he was "unaware" of the incident.
The reason for the protest was not immediately clear.
This is a developing story.
WATCH | Police unleash rubber bullets as protesters become violent in Joburg CBD
Law enforcement officers were attacked during a violent protest in the Johannesburg CBD on Thursday afternoon.
Johannesburg metro police spokesperson chief superintendent Wayne Minnaar said metro officers and SAPS police were responding to the protest in Rahima Moosa Street when they were attacked.
"Officers had to fire rubber bullets at the protesters to disperse them."
The situation remains tense.
Motorists were advised to use alternative routes.
Rea Vaya bus services said Ellis Park buses remain diverted and the Fashion Square North station remained closed.
Police spokesperson Xoli Mbele could not immediately comment, saying he was "unaware" of the incident.
The reason for the protest was not immediately clear.
This is a developing story.