President Francois Hollande has announced France will send artillery equipment to Iraq as part of increased military aid to fight Islamic State extremists, after the deadly Bastille Day lorry attack in Nice.

Mr Hollande said the equipment will be in place next month, as part of French efforts to boost its participation in the US-led fight against IS, which claimed responsibility for the Nice attack.

France has been conducting air strikes against IS and providing military training, but Mr Hollande reiterated that he would not send ground troops.

He spoke after an emergency security meeting in Paris, his fourth such meeting since Tunisian Mohamed Lahouaiej Bouhlel rammed through a Bastille Day event, killing 84 people.

Mr Hollande said 12 people wounded in the attack are still fighting for their lives.

Earlier, authorities in Nice refused a request from French anti-terror police to delete surveillance camera images of last week's deadly attack, amid growing questions over the scale of the police presence at the time.

The city received a letter this week from the SDAT anti-terrorism agency saying images of the July 14 attack should be destroyed, an official at Nice City Hall said.

The city is filing a legal complaint instead, arguing that the images could constitute evidence in the case, said the official.

The letter did not provide a reason for the request, the city official said, but Le Figaro newspaper said national police are concerned that the images would leak out and be used for jihadi propaganda.

The request comes as the government faces growing criticism over security measures the night of the attack, and the cameras could show where and how police were deployed.

Top regional official Christian Estrosi, of the conservative opposition Republicans party, had argued for tougher security for Nice's Bastille Day fireworks celebrations.

Interior Minister Bernard Cazeneuve acknowledged on Thursday that only lightly armed local police were guarding the entrance to a pedestrian zone on the beachfront promenade in Nice when Bouhlel sped past a barricade. Mr Cazeneuve had previously said national police were guarding the closed-off boulevard.

An internal police investigation into the security measures has been launched.

Five people were charged with terrorism offences late on Thursday night in connection with the attack. The Paris prosecutor says Bouhlel had accomplices and appears to have been plotting his attack for months, citing text messages, more than 1,000 phone calls and video of the attack scene on the phone of one of the suspects.

Nice City Hall has put up the names of all 84 people killed in the attack on two black banners. The victims were of several nationalities, as were the more than 300 people wounded in the attack.

AP