Nigeria’s President Muhammadu Buhari has said he is determined to end police brutality, introduce reforms and bring “erring personnel… to justice”.
His comments came after two days of protests sparked by a video of a man allegedly being killed by police.
The protest movement initially targeted the federal Special Anti-Robbery Squad (Sars), widely accused of unlawful arrests, torture and murder.
The protesters say they want the unit disbanded rather than reformed.
Previous commitments to change the behaviour of the police have not had an effect, critics say.
In a series of tweets, the president said that his government’s “determination to reform the police should never be in doubt”.
He added that he was being “briefed… on the reform efforts ongoing to end police brutality and unethical conduct”.
But he called for calm and emphasised that most police officers were committed to protecting Nigerians.
On Friday, in the capital, Abuja, police fired tear gas at protesters who were highlighting police harassment and brutality.
A police spokesman said minimum force had been used but demonstrators told the BBC that some people had been beaten and one said she had heard gunshots.
The hashtag #EndSARS was trending worldwide on Twitter on Friday with celebrities including the Nigerian superstars Wizkid and Davido tweeting their support for protesters.
British-Nigerian Star Wars actor John Boyega has also expressed his backing on social media.