French police are boosting security after an attack on officers in central France, and the country's top security official is visiting the city where a driver ran down 11 pedestrians.

The visit of Interior Minister Bernard Cazeneuve on Monday was an indication of the government's heightened concerns days after Islamic extremists renewed calls for individuals to attack in the West.

Counter-terrorist police are investigating Saturday's knife attack on police in a suburb of Tours, which left two officers seriously injured and the attacker dead. On Sunday, a driver with a history of psychiatric problems rampaged through Dijon. Cazeneuve was visiting those injured in the attack.

French-speaking Islamic State militants have called for attacks in the West, most recently in a video posted on jihadi forums on Friday.