(UPDATED) A car loaded with gas canisters rammed into a police van on the Champs-Elysees avenue in Paris on Monday, leaving the driver dead in what the interior minister said was an attempted attack.
Police sources told AFP that a Kalashnikov rifle, handguns and gas bottles were found in the white Renault Megane.
Video showed orange smoke pouring from the car after the impact as the vehicle sat in the middle of the prestigious avenue which is lined with shops and cinemas.
The police and the army have consistently been attacked by extremists in France.
"Security forces have been targeted in France once again," Interior Minister Gerard Collomb said, calling the incident an "attempted attack".
The weapons and explosives found in the vehicle "could potentially blow this car up," he added.
Interior ministry spokesman Pierre-Henry Brandet said bomb disposal experts were on the scene to "ensure the vehicle poses no further danger."
Later, the doors of the car and the bonnet were open as it was searched.
No police or bystanders were injured in the incident near the Grand Palais exhibition hall.
"People were running every which way," said a 51-year-old bystander who gave his name only as Alexandre. "Some shouted at me to get away."
Anti-terrorism prosecutors have opened an investigation.
Police closed two of the Metro stations on the Champs-Elysees, but two hours after the attack tourists were back taking selfies of the Arc de Triomphe and visiting shops.
Collomb said the attack "shows once again that the threat (of an attack) remains extremely high in France".
The incident came just two months after a policeman was shot and killed on the avenue, days before the first round of France's presidential election.
After that attack, a note praising the Islamic State group was found next to the body of the gunman, Karim Cheurfi, and weapons including a shotgun and knives were found in his car.
On June 7, a hammer-wielding Algerian man was shot and wounded by police after he struck an officer on the head in front of Notre Dame cathedral in Paris, shouting it was in revenge "for Syria".
He had pledged allegiance to the Islamic State group in a video found at his home.
String of attacks
The attack Monday was the latest of a string in France and Britain.
Earlier Monday, a van ploughed into a crowd of Muslims near a London mosque, injuring 10 people.
It was the second terror attack this month in the British capital.
Two weeks ago jihadists used a van and knives to crush and stab to death eight people enjoying a night out around London Bridge. Three of the victims were French.
In May, a suicide bomber killed 22 people, including children, at a concert by US singer Ariana Grande in Manchester.
France remains under a state of emergency imposed after the November 2015 attacks in Paris, when Islamic State jihadists slaughtered 130 people in a night of carnage at venues across the city.
Previous major attacks targeted the paris offices of the Charlie Hebdo satirical magazine in January 2015.
A senior police officer and his girlfriend were both killed by a radicalised man at their home in the Paris suburbs a year ago.
And in July last year, a radicalised Tunisian man knocked down and killed 86 people as he rammed a truck through a crowd watching Bastille Day fireworks in the Riviera city of Nice.
On Wednesday, the French government is to unveil a new anti-terrorism law, designed to allow the state of emergency to be lifted.
"To those who question the necessity of such laws, you can see that the state of France today necessitates it," Collomb said.
"If we want to effectively ensure the security of our citizens, we must be able to take a certain number of measures," he added.