People pay tribute to victims of knife attack outside Notre-Dame basilica in Nice, France, Oct. 30, 2020. France's vigilance against terrorism is raised to the highest level of "attack emergency" throughout the national territory following the knife attack in Nice, Prime Minister Jean Castex announced on Thursday. Early Thursday morning, a knife attacker stabbed to death three people at Notre-Dame basilica in central Nice. The alleged perpetrator has shot by police and transferred to hospital.Photo:Xinhua

A woman pays tribute to victims of knife attack outside Notre-Dame basilica in Nice, France, Oct. 30, 2020. France's vigilance against terrorism is raised to the highest level of "attack emergency" throughout the national territory following the knife attack in Nice, Prime Minister Jean Castex announced on Thursday. Early Thursday morning, a knife attacker stabbed to death three people at Notre-Dame basilica in central Nice. The alleged perpetrator has shot by police and transferred to hospital.Photo:Xinhua

A man pays tribute to victims of knife attack outside Notre-Dame basilica in Nice, France, Oct. 30, 2020. France's vigilance against terrorism is raised to the highest level of "attack emergency" throughout the national territory following the knife attack in Nice, Prime Minister Jean Castex announced on Thursday. Early Thursday morning, a knife attacker stabbed to death three people at Notre-Dame basilica in central Nice. The alleged perpetrator has shot by police and transferred to hospital.Photo:Xinhua

People pay tribute to victims of knife attack outside Notre-Dame basilica in Nice, France, Oct. 30, 2020. France's vigilance against terrorism is raised to the highest level of "attack emergency" throughout the national territory following the knife attack in Nice, Prime Minister Jean Castex announced on Thursday. Early Thursday morning, a knife attacker stabbed to death three people at Notre-Dame basilica in central Nice. The alleged perpetrator has shot by police and transferred to hospital.Photo:Xinhua