Aerial footage posted on Twitter shows police armed with automatic weapons storming the Notre Dame church. Ambulances and fire service vehicles were also at the scene where three people are confirmed to have died. The Nice Mayor told reporters the man suspected of carrying out a fatal knife attack at a church in the southern French city of Nice kept shouting “Allahu Akbar”.
Mayor Christian Estrosi said on Twitter the knife attack had happened in or near the city’s Notre Dame church and that police had detained the attacker.
Police said three people were confirmed to have died in the attack and several were injured.
A police source said a woman was decapitated.
French politician Marine Le Pen also spoke of a decapitation having occurred in the attack.
Mr Estrosi said: “Enough is enough.
“It’s time now for France to exonerate itself from the laws of peace in order to definitively wipe out Islamo-fascism from our territory.”
He added the victims had been killed in a “horrible way”.
“The methods match, without doubt, those used against the brave teacher in Conflans Sainte Honorine, Samuel Paty,” he said, referring to a French teacher beheaded earlier this month in an attack in a suburb of Paris.
The attack comes while France is still reeling from the beheading earlier this month of French middle school teacher Samuel Paty in Paris by a man of Chechen origin.
The attacker had said he wanted to punish Paty for showing pupils cartoons of the Prophet Mohammad in a civics lesson.
It was not immediately clear what the motive was for the Nice attack, or if there was any connection to the cartoons, which Muslims consider to be blasphemous.
Since Paty’s killing, French officials – backed by many ordinary citizens – have re-asserted the right to display the cartoons, and the images have been widely displayed at marches in solidarity with the killed teacher.
That has prompted an outpouring of anger in parts of the Muslim world, with some governments accusing French leader Emmanuel Macron of pursuing an anti-Islam agenda.