PARIS- French President Francois Hollande said Thursday's lethal attack on the southern city of Nice was clearly a terrorist assault and that the state of emergency imposed since a previous attack on Paris last November would be extended for another three months.Speaking after an emergency meeting in the early hours of Friday morning, Hollande said at least 77 people were killed in an attack in which the assailant drove a big truck at high speed into dense crowds who were watching a fireworks display on the country's national Bastille Day holiday."There's no denying the terrorist nature of this attack of yet again the most extreme form of violence," the French leader said in a national television address at 4 a.m.., about five or six hours after the carnage in Nice.