France had no reason to view the perpetrator of the Nice attack as a security risk, according to Interior Minister Gerald Darmanin, who has told the public to be ready for more brutal events.
"He wasn't on any of our security watch lists, either French or European," Mr Darmanin said on Friday. "We need to understand that there have been and there will be other events such as these terrible attacks."
The interior minister said the risk profile had been aggravated by "extremely strong calls to hatred from certain foreign leaders" targeting both himself and President Emmanuel Macron.
A French history teacher, Samuel Paty, was killed earlier this month after he displayed cartoons viewed as offensive by Muslims to students as part of a lesson on free speech.
Two French newspapers, Le Figaro and Liberation, reported on Friday that Mr Darmanin had already told regional authorities last Sunday to be on heightened alert for "individual" terror attacks.
The warning came after a media service called Thabat, which the interior ministry note said was "linked to Al Qaeda," called for retaliation against France following publication of cartoons by the satirical weekly Charlie Hebdo.
In his remarks, Mr Darmanin said there was a root cause of the attacks that was essentially ideological and encompassed cultural, lifestyle and emotional codes and behaviours. Terror represented a means of trying to impose control not an expression of divisions between faiths.
In the Nice attack on Thursday, Brahim Aouissaoui entered the church in the centre of the Mediterranean city at around 8.30am, according to France's anti-terrorism prosecutor Jean-Francois Ricard.
He slit the throats of a 60-year-old woman and Vincent Loques, a 55-year-old sacristan of the church.
He also stabbed Simone Barreto Silva, a 44-year-old Brazilian woman who was residing in France. Silva managed to flee but later died of her wounds.
Officials said Aouissaoui was taken to hospital after being shot and wounded by police.
The victims were "targeted for the sole reason that they were present in this church at that moment," said Mr Ricard, who added Aouissaoui was in a "life-threatening" condition.
This video documents how the day's frightful events unfolded.
More than 250 people have been killed in terror attacks on French soil since January 2015, when gunmen massacred 12 people at the offices of Charlie Hebdo over its content.
To mark the start of the trial for 14 suspected accomplices of the attackers, Charlie Hebdo republished the controversial cartoons last month.
Just days later, an 18-year-old man from Pakistan seriously injured two people with a meat cleaver outside Charlie Hebdo's former offices in Paris.
A cycle of violence has since unfolded around France.