Authorities declared a 24-hour curfew in Nigeria's economic hub Lagos Tuesday as violence flared in widespread protests that have rocked cities across the country.

Lagos state governor Babajide Sanwo-Olu announced only "essential service providers and first responders" would be allowed on the street from 4pm (1500GMT).

Protests that began 12 days ago over abuses by the Nigerian police's loathed Special Anti-Robbery Squad (SARS) have spiralled dramatically. 
Protests that began 12 days ago over abuses by the Nigerian police's loathed Special Anti-Robbery Squad (SARS) have spiralled dramatically.  AFP / Kola Sulaimon

"I have 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," he wrote on Twitter.

"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."

Two men attempt to bring down a wall during clashes between youths in the Nigerian capital Abuja
Two men attempt to bring down a wall during clashes between youths in the Nigerian capital Abuja AFP / Kola Sulaimon

Protests that began 12 days ago over abuses by the police's loathed Special Anti-Robbery Squad (SARS) have spiralled dramatically.

Some 18 people have died in the demonstrations as clashes have been reported between protesters and assailants dressed in civilian clothes.

Lagos, a city of 20 million, has been paralysed as crowds have blocked key roads and access to the international airport.

Nigerian police disperse protest with tear gas in Abuja
Nigerian police disperse protest with tear gas in Abuja AFPTV / Okunyomih John

Witnesses told AFP that a police station was set ablaze in the Orile Iganmu district of the city on Tuesday.

in the capital Abuja, crowds were violently dispersed by security forces Tuesday and thick black smoke could be seen over the city, an AFP photographer said.

Tensions were high after news of three deaths in the city during unrest on Monday.

"The command has launched an investigation into the matter and normalcy has been restored to the area," said police spokesman Mariam Yusuf.

"However, about three persons were reported dead and some cars damaged."

The government has announced the scrapping of SARS and a raft of reforms to the police in a bid to placate the protesters.

But many of the young demonstrators are sceptical of the official promises and their demands have grown to include more sweeping changes in Africa's most populous nation.