LAGOS, Nigeria

Hundreds of protesters swamped Nigeria’s commercial hub of Lagos on Monday to kickstart the so-called "RevolutionNow" movement, which organizers say is meant to force the government to do more to improve the lot of the masses.

The protest was called by activist and former presidential candidate Omoyele Sowore demanding "system change", a term the Nigerian government says is an attempt to overthrow the democratic government.

On Saturday, the secret police arrested and detained Sowore over activities they said were harmful to public peace amid criticisms by the civil rights movement, including Literature Nobel Laureate Wole Soyinka.

RevolutionNow protesters said Sowore’s detention would not stop the protest which they insisted was geared towards system change and an "end to oppression of the people" by the ruling political elites across party lines.

"We cannot be intimidated. We have a right under the constitution to stage a protest. We have a right to demand a better deal," Bolakale Abdullahi, a member of the Committee for the Defence of Human Rights, one of the bodies organizing the protest, told Anadolu Agency.

Protesters said they would also march in other cities of the country including the capital Abuja.

Security forces have been deployed at the National Stadium in Lagos amid the demonstrations. The protest almost turned violent with protesters charging at security agents who responded with teargas.

The government condemned RevolutionNow, calling it a veiled attempt to destabilize the country by those who lost elections.

"The President of Nigeria and his administration respect and uphold the right of every Nigerian to peaceful protest and civil campaign -- whether to raise awareness on issues, and even oppose the government," Garba Shehu, a presidential spokesman, said in a statement Sunday night.

"There is however a difference between peaceful call to protest and incitement for a revolution," he added.