Video report by ITV News Security Editor Rohit Kachroo
A church sexton has been named as one of the victims of a suspected terror attack in the French city of Nice.
Vincent Loques was named as one of the three victims who were fatally stabbed at the Notre Dame Church on Thursday morning.
Local politician, Eric Ciotti paid tribute to Mr Loques who he said was "extremely devoted to his church".
Sharing a photograph of Mr Loques, he tweeted: "I am thinking of his family, his loved ones and the whole Catholic community."
Mr Loques was 55 and a father of two, La Parisien newspaper reported.
Two women were also killed in the attack.
French national paper Le Monde reported that one of the victims, a woman, had her throat cut as the perpetrator tried to behead her.
Another woman was seriously injured in the attack - she took refuge in the church's cafe, where she died a few minutes later.
She is said to have told medics to tell her children that she loves them.
A suspect, a Tunisian migrant aged about 21, was seriously wounded by police as he was detained and has been taken to hospital in a life-threatening condition.
He had reportedly only recently arrived on a refugee boat via the Italian island of Lampedusa.
An official said the suspect is believed to have been acting alone and police are not searching for other attackers.
Following the attack, France raised its national security alert status to the highest possible level - "terror attack emergency".
The anti-terrorism prosecutor’s office said an investigation was opened into an attack with a terrorist connection.
Meanwhile, two other attacks happened on Thursday morning, although it was not immediately clear if they were linked to the Nice incident.
Police shot dead a man near the city of Avignon in southern France after he threatened a passerby with a handgun and a Saudi man was arrested on Thursday after a guard was attacked with a "sharp tool" outside the French embassy in Saudi Arabia.
According to Le Monde, a man was also arrested in Lyon. He was found wearing a tactical vest and was armed with a 30 cm knife. According to a police source, the individual had previously been reported to French intelligence services.
Nice Mayor Christian Estrosi posted on Twitter that the alleged perpetrator of the knife attack in the Basilica of Notre-Dame had been arrested.
The suspect is thought to have been acting alone and has not been named. The motive for the attack also remains unknown.
He said: "I am on site with the @PoliceNat06 and the @pmdenice who arrested the perpetrator of the attack. I confirm that everything suggests a terrorist attack in the Basilica of Notre-Dame #Nice06."
He told BFM television that three people had died - two inside the church and a third who fled but was fatally wounded.
A passerby's footage captures the moment gunshots at the Basilica of Notre-Dame were heard.
Images on French media showed the neighbourhood locked down and surrounded by police and emergency vehicles.
Later on Thursday morning, the lower house of parliament suspended a debate on new virus restrictions. The deputies, alongside Prime Minister Jean Castex, held a moment of silence for the victims.
On Thursday afternoon, French President Emmanuel Macron travelled to Nice to deliver a defiant message.
France's President Emmanuel Macron arrives in Nice on the afternoon of the attack
Outside the Notre-Dame Basilica, he said the attacks would not cause France to "give up [its] values".
He added that he would immediately increase the number of soldiers deployed to protect schools and religious sites from around 3,000 currently to 7,000.
Police described the incident as "very serious". In a post on Twitter, the force asked the public not to panic and to steer clear of the city centre.
They added that the bomb disposal teams have been carrying out a controlled explosion in the area.
Meanwhile, the Minister of the Interior, Gerald Darmanin, announced that a "crisis meeting" had begun.
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.”
Prime Minister Boris Johnson said he is "appalled" to hear about the "barbaric" attack in Nice.
"Our thoughts are with the victims and their families, and the UK stands steadfastly with France against terror and intolerance," he added.
Foreign Secretary Dominic Raab said the UK stands with France "in sorrow, shock and solidarity", while Home Secretary Priti Patel said the country is "ready to provide any support that the French government needs at this really crucial time".
UK Home Secretary Priti Patel said she's "devastated" for the people of France
Other world leaders also paid tribute to the people of France.
US President Donald Trump said on Twitter: "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 it!"
German Chancellor Angela Merkel voiced her solidarity with her neighbouring country.
In a tweet posted by her spokesman, she said: "I am deeply shaken by the brutal murders in the church in Nice.
"My thoughts are with the relatives of those murdered and injured. Germany stands with France at this difficult time."
A spokesman for UN Secretary-General Antonio Guterres said he "strongly condemns the heinous attack".
"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.
The events come as France is under high alert for terrorism amid tensions over the publication of caricatures of the Muslim prophet Muhammad and after two other recent attacks.
Mr Estrosi tweeted that 13 days after a terrorist killed teacher Samuel Paty, France can "no longer be satisfied with the laws of peace to annihilate Islamo-fascism".
He added that the attacker shouted “Allahu akbar!” repeatedly as police apprehended him and that “the meaning of his gesture left no doubt.”
The attack happened less than a kilometre from the site in 2016 where another assailant plowed a truck into a Bastille Day crowd, killing dozens.