Maya Vidon and Doug Stanglin

USA TODAY

NICE — French prosecutor Francois Molins said Friday that the driver of a truck that plowed into a crowd of seaside spectators in Nice, killing 84 people, was a Tunisia-born Frenchman who had a petty criminal record but was not known to any intelligence services, local or national, as having links to radicalism.

French Prime Minister Manuel Valls said later Friday, however, that the attacker was "probably linked to radical Islam," AFP news agency reported.

"He's a terrorist who is probably linked to radical Islam in one way or another," Valls told French television.

Molins, the anti-terrorism prosecutor, identified the suspect, who was shot and killed by police during the attack, as Mohamed Bouhlel, 31, a local delivery man. He said Bouhlel's house had been searched and that his wife was detained for questioning. In Tunisia, Bouhlel's parents, sister and close friends were detained for questioning, according to the BBC.

Speaking to reporters hours after an update by French President Francois Hollande, Molins said 202 people were injured in the melee at the Bastille Day celebration Thursday evening, and that 52 remained in critical condition, half of them still in a coma and 25 on life-support. He said 10 children were among the dead, which included two Americans.

Molins said Bouhlel, driving a large, white refrigerated truck, mowed down scores of people along a one-mile stretch of the Promenade des Anglais during an annual fireworks display. He said police eventually shot and killed him in the truck's cab as he continued to run down people along the walkway.

Molins said police recovered a cellphone, identification papers, and a bank card in the cab of the truck along with a handgun, ammunition and a gas grenade, along with replicas of other weapons.

He said Bouhlel was identified through his fingerprints and was known to local courts and police. He had been convicted on charges of theft and making violent threats between 2010 and 2016, and received a six-month suspended sentence in March on a weapons charge.

Molins said suspect, who was born in Tunisia, was "totally unknown to intelligence services ... and was never placed on a watch list for radicalization.”

The prosecutor said surveillance video showed that the truck had been parked on a Nice street on Wednesday and that Bouhlel, arriving on a bicycle, picked it up on Thursday, putting the bike in the back.

He said officials were investigating how Bouhlel obtained the truck and whether he had any accomplices in the attack.

President Obama, addressing the Washington diplomatic corps at a reception Friday, said he faced the group with a heavy heart.

"Overnight in Nice, we witnessed another attack, an appalling attack on freedom and the peace that we cherish," the Voice of America quoted the president as saying. "Today, our hearts are with the people of France and all the innocent men and women and so many children who were hurt or killed in this sickening attack."

White House spokesman Josh Earnest, speaking to reporters Friday evening, said the administration is still working under the theory that the rampage was a terrorist attack.

President Obama spoke with President Holland earlier Friday and members of the administration, including Homeland Security secretary Jeh Johnson, spoke with their French counterparts, Earnest said.

Thursday's situation was the worst terrorist attack in France since 130 people were killed in Paris in November and is likely the deadliest rampage ever by a lone attacker.

Hollande, who flew to Nice on Friday, said earlier that the attack was carried out "to satisfy the cruelty of an individual, maybe a group" and called on the French people to maintain their "unity and cohesion" in the face of the tragedy.

"We are dealing with a struggle that will take a long time, because we have an enemy who will continue to strike all peoples, all countries that have freedom as a fundamental value," he said.

Hollande, who described the attack as "despicable," extended the nation's state of emergency, due to expire this month, for another three months, and will supplement the 7,000 troops securing critical sites around France with a call up of reserves tasked with tightening border security.

"We can overcome this evil because we are France, as one," he added..

Prime Minister Valls has announced three days of national mourning, starting Saturday.

"We will not give in to terrorist threats," he said. "We are in a new era. France has been struck once again in her flesh. They wanted to harm the very idea of national unity."

The U.S. State Department confirmed that two vacationing Americans were among those killed. They were identified as Sean Copeland, 51, and his 11-year-old son, Brodie, of Austin.

“We are heartbroken and in shock over the loss of Brodie Copeland, an amazing son and brother who lit up our lives, and Sean Copeland, a wonderful husband and father,” the family said in a statement, the newspaper reported. “They are so loved.”

In Washington, President Obama, addressing the diplomatic corps at the White House, said he spoke with Hollande Friday and pledged "to stand with our French friends as we defend our nation against this scourge of terrorism and violence."

"We cannot give in to fear," he said. "That's what terrorists want. We should never do their work for them."

On Friday morning, a huge section of the famous promenade in Nice was closed off, and victims and families of the dead who came to pay their respects to the fallen were unable to access the scene to lay flowers, light candles or mourn there.

Bastille Day attack in France: What we know

Off the promenade, police ships stood as a reminder that this city is under partial lockdown: City officials advised residents to stay home.

Tourists, here on the French Riviera during its busiest season, were unsure what to do, milling around, wondering what would actually be open – the beach was closed. Police officers in boats were stopping along the shore to tell them to leave.

Some like Ruth Tobassen of Norway who arrived Thursday with her husband decided to switch hotels after the attacks the night before.

She and her husband decided against attending the fireworks because "we were so hungry" after we arrived. Because it was too windy, they also decided to avoid the terrace and sit inside the restaurant.

"A bunch of people ran in, in panic," she recalled. "They were looking for people they lost, couldn't find them. A grandfather sitting with a child in his lap on the floor just cried. It was tragic."

Writing online, Nice Matin journalist Damien Allemand, who was at the waterside, said the fireworks display had finished and the crowd had got up to leave when they heard a noise and cries.

“A fraction of a second later, an enormous white truck came along at a crazy speed, turning the wheel to mow down the maximum number of people,” he said. “I saw bodies flying like bowling pins along its route. Heard noises, cries that I will never forget.”

French President Hollande: 'Horror again has struck France'

The two presumptive presidential candidates, Donald Trump and Hillary Clinton, were quick to address the attack.

Republican Trump tweeted that "In light of the horrible attack in Nice, France, I have postponed tomorrow's news conference concerning my Vice Presidential announcement." He told Bill O'Reilly of Fox News that he would ask Congress for a declaration of war, if he were president.

Democrat Clinton told CNN's Anderson Cooper that "it's clear we are at war with these terrorist groups, but it's a different kind of war, and we have to be smart about how we wage it and win it."

Trump postpones veep announcement after France attack

The terror attack came at the height of the summer tourism season in Nice, one a string of resort cities along France's southern coast.

Witnesses described scenes of unimaginable panic and bloodshed that has become a numbing refrain in the wake of recent terrorist attacks that include suicide bombings at the Istanbul airport on June 28 and shooting and machete murders in Dhaka, Bangladesh, on July 1.

Images and video broadcast on social media show the truck streaming through a crowd at a high rate of speed, followed by dozens dashing from the scene. One photo appears to show several bullet holes in the truck's windshield after police fired upon it. Other photos show bodies covered in tarps.

"Thank God we decided not to take the young ones" to see the Bastille Day fireworks, witness Yves Lamorelle said. "I am the only one who went. It was completely crazy, the crowd panicked and everyone was trying to flee."

"I was having a drink but after a few minutes people started running toward us from the promenade ... Then all the cafe terraces started to clear out in a scary type of chaos. The tables, the chairs, the glasses got turned over. People were stepping on top of each other without even knowing why."

Witnesses to Nice horror: Bodies everywhere

Voices: From the Bataclan to Nice, darkness falls over France

The attack was the latest in a series of terror incidents to hit the country in the past two years.

On Jan. 7, 2015, Islamist militant brothers Cherif and Said Kouachi attacked the Charlie Hebdo magazine offices in Paris, beginning three days of terror that left 17 people dead. The victims included a policewoman and hostages at a kosher grocery who were killed by another militant, Amedy Coulibaly. All three attackers were killed in standoffs with police. Al-Qaeda in the Arabian Peninsula claimed responsibility.

On Nov. 13, 2015, 130 people died in a series of coordinated attacks across Paris that included explosives and shots fired at a concert hall during a performance by Eagles of Death Metal, a California rock band. Islamic State claimed responsibility for the attacks.

Contributing: Jabeen Bhatti in Berlin; Doug Stanglin, Matthew Diebel and Jessica Durando in McLean, Va.; Melanie Eversley and Marco della Cava, and The Associated Press