The Executive Secretary of Anti-Corruption Network and former member of the House of Representatives, Mr. Dino Melaye
They were protesting against what they described as "impunity in Rivers State and abuse of office by the state Commissioner of Police, Mr. Joseph Mbu."
During the protest, tear gas canisters were fired indiscriminately even at journalists. Some of the protesters slumped and fainted in the process.
The battle-ready policemen had earlier condoned off the Federal Secretariat area, Abuja, where the protest was billed to hold.
The ACN protesters, in their bid to hold the rally, decided to march from the organisation's office to the secretariat, but met an unyielding police blockade.
The security operatives fired tear gas canisters at the demonstrators, which resulted in a stampede, with some sustaining injuries.
While describing the situation in Rivers as "endemic, systemic and becoming contagious," the ACN boss said for Nigeria to be rescued, "we should stand up
He said, "We must do everything to rescue this country from the hands of these economic canker worm. There is intimidation, incessant arrests, threats and assassination attempts on my life.
But for me, I am resolute because the battle to deliver this country from economic canker worms, financial vultures and inept leadership, as I have repeatedly said, is a battle of no retreat, no surrender."
Nigerians, he said, must creep out of their cocoons and become change agents.
Melaye added, "We need to call a bloodless revolution that will transform this nation from the hands of these economic canker worms and financial scavengers.
Nigeria is not only sick but also suffering from a dreadful continental abnormality.
In an unjust society, silence is a crime, this is the time in the history of Nigeria where silence is no longer golden.
People must come out and speak because the day you stop eating is the day you start dying.
Where dictatorship becomes legalised, revolution becomes a right."