Armed operatives of the Department of State Services on Tuesday in Abuja opened fire at the protesters, who gathered to demand the release of detained activists Omoyele Sowore and Olawale Bakare.
The operatives fired live ammunition and teargas canister at the protesters and journalists at close range injuring many of them.
The peaceful protest commenced at 12:00pm at the Aso Drive Junction.
Trouble started when a vehicle belonging to the DSS rammed into the protesters, injuring many in the process.
Shortly afterwards, the operatives began to shoot at protesters and journalists, who also vandalised several vehicles around the vicinity.
Two journalists with Guardian Newspaper and Galaxy TV, Richard Oludare and Walter, were beaten and seriously injured by the DSS officials.