PARIS (AFP) - French Prime Minister Manuel Valls stepped up security nationwide Tuesday following three successive, apparently unrelated bloody attacks, in a bid to ease growing unease in the country.
While the motives behind the incidents - a knife attack on police and two car rampages onto passers-by - remain unclear, the violence has jarred nerves after repeated militant calls for "lone wolf" action in France over its fight against Islamic extremism.
Altogether, 26 people were injured in the attacks, one of whom was pronounced clinically dead on Tuesday.
Valls stressed that the three incidents were "distinct", urging the French to keep calm while stressing security would be heightened.
"Two hundred to 300 extra soldiers will be deployed in the coming hours" on top of 780 forces already mobilised, he said live on television.
Security patrols will also be increased in shopping areas, city centres, stations and on public transport, he added.
The violence began on Saturday when a man was shot dead after attempting to enter a police station in the central town of Joue-les-Tours while shouting "Allahu Akbar" and attacking three officers with a knife, two of whom were seriously injured.
Then on Sunday evening, a driver ploughed into pedestrians in Dijon in the east, injuring 13 people and also shouting the same Islamic phrase which means "God is greater" and has in the past been used by extremists when waging violent attacks.
And on Monday night, another man rammed into a bustling Christmas market with his car in the western city of Nantes, injuring 10 people - one of whom is now clinically dead - before stabbing himself repeatedly and being arrested.
DON'T 'GIVE IN TO FEAR'
The attacks both differ widely and present disturbing similarities, and Valls acknowledged there could be a copycat effect.
"Unbalanced individuals can act. They can be receptive to or influenced by propaganda messages or the power of images," he said.
Authorities have for months been on tenterhooks over the threat of violence inspired by Islamic extremism.
In September, the radical Islamic State in Iraq and Syria (ISIS) group that controls swathes of Iraq and Syria urged Muslims around the world to kill "in any manner" those from countries involved in a coalition fighting its militants, singling out the French.
Among instructions detailing how to kill civilians or military personnel was to "run him over with your car."
But while the probe into Saturday's attack is veering towards extremism - the Burundian convert to Islam who assaulted police had posted an ISIS flag on his Facebook page - the car rampages appear to have been committed by people with psychological problems.
Both prosecutors in charge of probing these incidents insisted they were not "terrorist acts".
The assailant in Dijon, for instance, had been to psychiatric hospitals 157 times, local prosecutor Marie-Christine Tarrare told reporters.
She said he told police that he ploughed into people due to a sudden "outburst of empathy for the children of Chechnya" and had shouted "Allahu Akbar" to give him courage.
Interior Minister Bernard Cazeneuve meanwhile said the attacker in Nantes also appeared to be "unbalanced" and not motivated by politics or religion.
A source close to the investigation said that after slamming into shoppers, the driver stabbed himself in the chest "at least nine times", causing himself serious injuries.
"We must not panic, lump things together, give in to fear," warned President Francois Hollande on a trip to overseas French territory Saint-Pierre-et-Miquelon.
Nevertheless, the government faced criticism on Tuesday that it was minimising the threat, at a time when more than 1,000 nationals are thought to be involved in waging militant war on home soil, or in Syria and Iraq.
Saturday's assailant Bertrand Nzohabonayo was not on a domestic intelligence watch-list but his brother Brice is well known for his radical views and was arrested in Burundi soon after the incident.
Nzohabonayo's mother had also told authorities that she was worried about Brice's radicalisation and "the influence he could have on his brother Bertrand," said Paris prosecutor Francois Molins, whose office is in charge of the probe.
The assailant in Dijon, meanwhile, had taken an interest in religion and started wearing a djellaba - a long robe worn in Muslim countries - just a week ago, according to his mother.