A lorry has struck a crowd after Bastille Day celebrations in the southern French city of Nice, killing at least 80 people and injuring dozens, officials say.
It happened on the famous Promenade des Anglaisafter a firework display. The driver was "neutralised", and guns and grenades were found inside the lorry.
Officials said it was an attack, and asked people to stay indoors.
About 50 people were injured, some critically, in the incident on Thursday evening.
Some reports spoke of shots being exchanged between police and the occupants of the lorry but these have not been confirmed.
Social media video showed people running through the streets in panic following the incident.
A journalist with the Nice Matin newspaper reported from the scene that there was "a lot of blood and without doubt many injured".