• At least three people, two women and a man, have been killed, including one woman who was decapitated. The man is reportedly the sexton of the church. The man has been identified locally as Vincent Loquès, a 45-year-old father of two.
• The suspected attacker has been identified as Brahim Aoussaoui, a 21-year-old Tunisian migrant who arrived in France from the Italian island of Lampedusa in October. He is reportedly unknown to French security services.
• Nice mayor Christian Estrosi said it was a terrorist attack, and the "Islamo-fascist" assailant "didn't stop shouting Allahu Akhbar even under medication" after being shot and arrested.
• President Emmanuel Macron has delivered a defiant message, saying the attacks would not force France to "give up our values".
An attacker armed with a knife killed three people inside a church in the Mediterranean city of Nice, beheading one of his victims, an elderly woman.
The attack on Friday morning (NZT) prompted the government to raise its security alert status to the highest level and double the number of soldiers deployed in the country, with President Emmanuel Macron saying France "will not give any ground".
The Nice suspect has been named as Brahim Aoussaoui.
He entered the church with a large knife and reportedly decapitated a 60-year-old woman whose dying words were, "Tell my children that I love them".
He stabbed to death the church's 55-year-old sacristan and left a third victim, a 44-year-old woman - so badly injured that she died from her wounds at a nearby restaurant having fled the scene.
Police say Aouisaoui was born in Tunisia in 1999 and arrived in Europe as recently as Wednesday.
He was originally from the village of Sidi Omar Bouhajla, near Kairouan, but had moved to Sfax with his family before heading to Europe.
France's anti-terrorism prosecutor Jean-Francois Ricard says he travelled from Tunisia to the Italian city of Lampedusa on September 20.
He was placed in coronavirus quarantine before being released. He travelled to Paris on October 9 but did not make a bid for political asylum, The Guardian reports.
A Tunisian official told Al Jazeera that the killer arrived in Nice on Wednesday and was carrying an Italian Red Cross card. He was not on Tunisia's suspected militant list and there were no red flags, the official said.
It is believed he travelled by train - using the Red Cross identity document - and changed clothes at a train station in Nice before walking to the church early on Thursday morning where he began his attack.
French politician Eric Ciotti named the sexton killed in the attack as Vincent Loquès, a man who was "extremely devoted to his church".
Pensées pour Vincent Loquès, sacristain de la basilique Notre Dame de Nice lâchement assassiné par un terroriste islamiste.
Il était extrêmement dévoué à son église, je pense à sa famille, ses proches et à l’ensemble de la communauté catholique. pic.twitter.com/saBjEc1WDj
It was the third attack in two months in France that authorities have attributed to Muslim extremists, including the beheading of a teacher.
It comes during a growing furore over caricatures of the Prophet Muhammad that were republished by the satirical newspaper Charlie Hebdo - renewing vociferous debate in France and the Muslim world over the depictions that Muslims consider offensive but are protected by French free speech laws.
Other confrontations and attacks were reported on Thursday in the southern French city of Avignon and in the Saudi city of Jiddah, but it was not immediately clear if they were linked to the attack in Nice.
President Macron said he would immediately increase the number of soldiers deployed to protect schools and religious sites from around 3000 currently to 7000. French churches have been ferociously attacked by extremists in recent years, and Thursday's killings come ahead of the Roman Catholic All Saints' holiday.
BREAKING: French President Emmanuel Macron says "France is under attack" after three people died in a knife attack in Nice.
"He cried 'Allah Akbar!' over and over, even after he was injured," said Nice Mayor Christian Estrosi. "The meaning of his gesture left no doubt."
Estrosi praised police for their "composure and heroic demeanour" which enabled the "swift neutralisation of this barbarian" while still in the basilica.
Merci à nos policiers municipaux et à toutes les autres forces de l'ordre mobilisées. C'est leur sang-froid et leur comportement héroïque qui a permis la neutralisation rapide de ce barbare alors qu'il se trouvait encore dans la #BasiliqueNotreDame.
The suspect was shot but not fatally wounded when French police arrived on the scene and he advanced towards them with the knife. He was taken into custody.
"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," Estrosi said.
The revelation that Aouissaoui landed in late September on the tiny island south of Sicily sparked a major political row in Italy.
Italian authorities reportedly placed him in quarantine for two weeks onboard a ship, the Rhapsody.
They then released him, telling him to leave Italy.
Instead, he travelled to the southern city of Bari, in the region of Puglia, and from there made his way to France in early October.
Matteo Salvini, the head of the League party, accused the government of being too lax on immigration controls and called for the resignation of the interior minister, Luciana Lamorgese.
"If it is confirmed that the attacker landed on Lampedusa in September, then went to Bari and then fled, then we will ask for the resignation of the interior minister," said Salvini, who was interior minister and deputy prime minister until last summer, when his coalition government collapsed.
President Trump offered his condolences to the people of France, saying he stands by America's "oldest ally".
"Our hearts are with the people of France. America stands with our oldest ally in this fight. These Radical Islamic terrorist attacks must stop immediately. No country, France or otherwise can long put up with," he tweeted.
The killings took place at Nice's Notre Dame Basilica, less than a kilometre from the site in 2016 where another attacker plowed a truck into a Bastille Day crowd, killing dozens of people.
Shots punctuated the air and witnesses screamed as police stationed at the grandiose doors to the church appeared to fire at the attacker inside, according to videos obtained by The Associated Press.
Hours later, AP reporters at the scene saw emergency vehicles and police tape lining the wide Notre Dame Avenue leading toward the plaza in front of the basilica. For a time after the attack, sounds of explosions could be heard as sappers exploded suspicious objects.
BREAKING: French president says he will more than double number of soldiers deployed to protect against attacks to 7,000. https://t.co/EAD2NomXZf
France's anti-terrorism prosecutor's office opened an investigation into the attack, the third one since a trial opened in September for people linked to the 2015 attacks at Charlie Hebdo and a kosher supermarket by gunmen who claimed allegiance to the Islamic State group and al-Qaida.
The trial is nearing its end, with a verdict planned for November 13, the fifth anniversary of another series of deadly Islamic State attacks in Paris.
Thursday's attacker was believed to be acting alone and police were not searching for other assailants, said two police officials, who were not authorised to be publicly named.
"With the attack against [teacher] Samual Paty, it was freedom of speech that was targeted. With this attack in Nice, it is freedom of religion," Prime Minister Jean Castex told lawmakers Thursday.
UN Secretary-General Antonio Guterres joined in international condemnation of the Nice attack.
Guterres "strongly condemns the heinous attack today that took place in Notre Dame's Basilica in Nice," spokesman Stephane Dujarric said.
"He extends his condolences to the families of the victims and reaffirms the solidarity of the United Nations with the people and the Government of France," the spokesman added.
Earlier, the lower house of parliament suspended a debate on France's new virus restrictions and held a moment of silence for the victims. Castex rushed from the hall to a crisis center overseeing the aftermath of the Nice attack and later returned to announce the alert level increase.
Macron, who has defended Charlie Hebdo's right to publish the caricatures, arrived in Nice later in the day.
Speaking from the scene, he said France had been attacked "over our values, for our taste for freedom, for the ability on our soil to have freedom of belief".
"And I say it with lots of clarity again today: we will not give any ground."
Muslims have held protests in several countries and called for a boycott of French goods in response to France's stance on caricatures of Islam's most revered prophet, whose birthday was marked in several countries Thursday. Soon before Thursday's attack, supporters of religious political party Jamiat Ulema-e-Islam protested in Pakistan against Macron.
In Avignon on Thursday morning, an armed man was shot to death by police after he refused to drop his weapon and a flash-ball shot failed to stop him, one police official said. And a Saudi state-run news agency said a man stabbed a guard at the French consulate in Jiddah, wounding the guard before he was arrested.
Islamic State extremists had issued a video on Wednesday renewing calls for attacks against France.
Many groups and nations, however, issued their condolences Thursday, standing firmly with France.
The French Council of the Muslim Faith condemned the Nice attack and called on French Muslims to refrain from festivities this week marking the birth of Muhammad "as a sign of mourning and in solidarity with the victims and their loved ones".
Turkey's Foreign Ministry strongly condemned the attack in Nice. "We stand in solidarity with the people of France against terror and violence," the statement said.
Relations between Turkey and France hit a new low after Turkey's president on Saturday accused Macron of Islamophobia over the caricatures and questioned his mental health, prompting Paris to recall its ambassador to Turkey for consultations.
The attack in Nice came less than two weeks after another assailant beheaded a French middle school teacher who showed the caricatures of the Prophet Muhammad for a class on free speech. Those caricatures were published by Charlie Hebdo and cited by the men who gunned down the newspaper's editorial meeting in 2015.
In September, a man who had sought asylum in France attacked bystanders outside Charlie Hebdo's former offices with a butcher knife.
French Roman Catholic sites have been ferociously and repeatedly targeted by extremists in recent years, including the killing of the Reverend Jaqcues Hamel, who had his throat slit while celebrating Mass in his Normandy church by Islamic militants and a plot to bomb Paris' Notre Dame cathedral.
Those attacks were claimed by the Islamic State group, which also is believed to have recruited a man now on trial who plotted unsuccessfully to attack a church on the outskirts of Paris.
Nice's 19th-century basilica Notre Dame de l'Assomption is the largest church in the city, but smaller and newer than the cathedral 1 mile (2 kilometers) away. The basilica's twin neogothic towers, standing 65 metres high, are a landmark feature in the heart of the city.