The governor of Nigeria's commercial hub, Lagos, has announced an indefinite 24-hour curfew in the state saying that protests against police brutality have "degenerated" into violence.

Babajide Sanwo-Olu said that criminals had hijacked the demonstrations "to unleash mayhem on our state".

Lagos has seen some of the largest of the recent wave of protests in Nigeria spearheaded by young people.

They began with a call for the disbandment of a notorious police unit.

President Muhammadu Buhari dissolved the Special Anti-Robbery Squad (Sars), accused of illegal detentions, assaults and shootings, on 11 October.

But the demonstrators have called for wider reforms in the security forces as well as changes in the way that the country is run.

In a series of tweets, Mr Sanwo-Olu said that he had "watched with shock how what began as a peaceful #EndSARS protest has degenerated into a monster that is threatening the well-being of our society".

"Lives and limbs have been lost as criminals and miscreants are now hiding under the umbrella of these protests to unleash mayhem on our state... we will not watch and allow anarchy in our dear state."

... of these protests to unleash mayhem on our state. As a government that is alive to its responsibility and has shown a commitment to the movement #ENDSARS, we will not watch and allow anarchy in our dear state.

— Babajide Sanwo-Olu (@jidesanwoolu) October 20, 2020

The curfew will come into force at 16:00 local time and will affect millions of people.

Only essential workers will be allowed out. The announcement by the Lagos governor follows reports that people set fire to a police station in the Orile part of Lagos state.

Videos posted on social media show the police station burning, with people standing outside cheering.

It is not clear if there were officers inside the building at the time or how the perpetrators managed to set the building aflame.

Peaceful protesters have feared that their cause could be hijacked by more violent elements, the BBC's Nduka Orjinmo in the capital, Abuja, says.