French authorities on July 15 were working frantically to discover the motives and any possible terrorist connections of a Tunisian man who drove a truck through a crowd celebrating Bastille Day in the southern city of Nice late on July 14, killing at least 84 people.
The attacker, identified as 31-year-old Mohamed Lahouaiej Bouhlel, was shot by police following his deadly rampage along Nice’s famed Promenade des Anglais seafront as he fired a gun at the crowd. It was the third attack with mass casualties on French soil in the past 19 months.
Paris prosecutor Francois Molins, who took over the investigation, said on July 15 that while no one has claimed responsibility, the attack "bears the hallmark of terrorist organization" and that investigators "will try to determine whether he benefited from accomplices."
Molins said the dead in Nice included 10 children and teenagers. He also said 52 of the 202 people left injured by the attack are in critical condition, 25 of them on life support.
He said that Bouhlel's documents were found inside the truck, adding that the attacker’s wife -- from whom he was reportedly separated -- was in custody.
In Focus: Tunisia's Double-Edged Revolution
Bouhlel, a Tunisian national who had French residency papers, reportedly had lived in France since 2005. Molins said he had previous run-ins with police but was not known to intelligence services.
"He had a police and judicial record for threats, violence, theft, and acts of criminal damage between 2010 and 2016, and had been sentenced by the Nice criminal court to a six-month term, suspended, on March 24, 2016, for violence with arms, committed in January 2016,” the prosecutor said.
"On the other hand, he was totally unknown to intelligence services, nationally and locally, and was never flagged for signs of radicalization," Molins added.
French Prime Minister Manuel Valls said on July 15 that the attacker "is a terrorist probably linked to radical Islam one way or another."
"Yes, it is a terrorist act and we shall see what the links there are with terrorist organizations," Valls told France 2 television.
French Interior minister Bernard Cazeneuve, however, said he could not confirm whether the attacker had ties to a radical Islamic organization.
WATCH: France Stunned By Another Mass Killing
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France Stunned By Another Mass Killing, This Time In Nice
The attacker drove the truck at high speed for about 2 kilometers along the Promenade des Anglais, mowing down celebrants after a fireworks display marking the French national day and leaving a horrific trail of carnage.
Nice's Mayor Christian Estrosi said the man also opened fire on the crowd before he was shot and killed by police. Several of the victims reportedly died of gunshot wounds.
Reports said an "inactive" grenade was found inside the truck, in addition to "several fake rifles."
France had mobilized extra security for the national day of celebration commemorating the storming of the Bastille prison in 1789. Approximately 11,500 security personnel were on hand for the traditional military parade in Paris.
The attack heightened security concerns across Europe and the United States following a wave of terrorist attacks by Islamic State (IS) militants and supporters of the extremist group in major Western cities.
French President Francois Hollande announced on July 15 that he was calling up the "operational reserve" of French security forces to reinforce gendarmes, police, and army troops that already have been deployed as heigthened security across France.
Comprised of all reservists who have once served in the French security forces, call up is expected to bring an addition 26,000 out of more than 200,000 reservists onto the streets of France.
Earlier, in a televised address to the nation, Hollande condemned the attack as a "terrorist" act and a "monstrosity." He vowed that France "will always be stronger, I promise you, than the fanatics that want to strike it."
"Nothing will make us yield in our will to fight terrorism," the French president said.
"We will further strengthen our actions in Iraq and in Syria. We will continue striking those who attack us on our own soil," he said in an allusion to IS, whose sympathizers have been blamed for a string of terrorist attacks in France and Belgium in the past two years, including coordinated attacks by multiple gunmen and bombers that killed 130 people in Paris in November.
Hollande convened a security cabinet meeting on July 15.
WATCH: U.S. Secretary Of State John Kerry Condemns Nice Attacks
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Kerry Condemns Nice Attack At Moscow Talks
He has extended by three months the state of emergency imposed after the Paris attacks.
The death toll in Nice includes foreigners -- at least two Americans, two Armenians, a Russian, and a Ukrainian have so far been identified.
But the setting of the attack, at the height of summer tourist season in one of the French Riviera's most glamorous cities, suggests those numbers could rise.
'Criminal And Unjustifiable'
Expressions of outrage and sympathy for the victims poured in from around the world.
U.S. President Barack Obama said that the United States would not be deterred in its fight against IS militants, using a July 15 White House reception for foreign diplomats to voice solidarity with France and vow to continue to fight against terrorism.
"These individuals and these networks are an affront to all our humanity," Obama said. "We will not be deterred. We will not relent."
The White House said earlier in the day that Obama ordered U.S. government flags to fly at half-staff to commemorate the victims of the attack and spoke with Hollande to "relay his condolences to the people of France on behalf of the American people."
White House spokesman Josh Earnest told reporters in Washington that Obama also "offered significant security cooperation" to France as well as "any assistance that they need to conduct their investigation and to take steps to try to prevent something like this from happening again."
Roman Catholic Pope Francis said via Twitter that he was praying for the victims and their families, adding, "I ask God to convert the hearts of the violent blinded by hate."
The United Nations Security Council in a statement strongly condemned the "barbaric and cowardly terrorist attack," which it called "criminal and unjustifiable."
European Council President Donald Tusk said Europe “will stand united with the families of victims, the French people, and the government in the fight against violence and hatred.”
Russian President Vladimir Putin expressed solidarity and called it an "outrageous terrorist attack" that exposed "brutality and cynicism" that was "shocking."
Chinese Prime Minister Li Keqiang expressed condolences and said “we strongly condemn terrorism in all forms.”
Vehicle attacks have been used by isolated members of militant groups in recent years, notably in Israel, though never to such devastating effect.
Nice, a city of around 350,000, is renowned as a glitzy resort but also has poor neighborhoods. As many as 130,000 Tunisians live in the city, and dozens of its Muslim residents have traveled to Syria to fight, a path taken by previous IS attackers in Europe.
Authorities on July 15 reopened Nice's Cote d'Azur Airport without incident after a brief evacuation prompted by an unattended bag in one of the terminals that turned out to be harmless.
Further details began to emerge about Bouhlel, who lived in a four-story building in one of Nice’s working-class neighborhoods where crime scene investigators and armed police were working on July 15.
Bouhlel was from the town of Msaken in Tunisia, about 10 kilometers from the city of Sousse, where an attacker shot and killed 38 people in 2015 -- mainly vacationers from Britain. Many people from that region have moved to France.
Molins said Bouhlel had three children but was separated from his wife. His relatives and neighbors described him as a tense, unfriendly man who was not religious.
French Justice Minister Jean-Jacques Urvoas said Bouhlel was convicted in March over a road-rage incident in which he “hurled a wooden pallet” at another man.
He was given a six-month suspended sentence and was required to check in with police once a week, a condition that Bouhlel had complied with.