France has suspended the use of stun grenades for policing student protests that have swept the country, after a 15-year-old's hand was blown off earlier this week.

Interior Minister Laurent Nuñez said he had requested the pause until the facts of Monday's incident in Lens had been "clarified", with conflicting accounts offered by protesters and officials.

The disruption continued on Wednesday with more than 500 schools fully or partially shut.

Prime Minister Sébastien Lecornu has defended the police response, after several groups complained of police using disproportionate force towards teenagers.

In an address to the nation on Wednesday evening, he denied security forces had "orders to confront" the young people.

He said the government would look into the demands made by students and promised they would present a set of proposals at the end of October, ranging from renovating buildings to make more teachers available. He gave no further details.

The "anger of young people does not come from nowhere," he said.

Education Minister Édouard Geffray said 24 schools had been "set alight or vandalised" to such an extent that they would be shut for several weeks, affecting 30,000 pupils.

Hundreds of thousands of people took to the streets on Tuesday to call for better school conditions and in some cities tear gas and water cannon were deployed. The interior ministry said 488 people were arrested and 43 members of the security forces were hurt.

Nuñez told French radio RTL that police watchdog IGPN had opened 18 investigations to determine whether officers had been "proportionate" during the demonstrations, which have spread from high school pupils to their parents, university students and unions.

Geffray said dozens of headteachers and deputies had been injured, many deliberately so, and alleged the movement had been "very quickly infiltrated by ultra-violent groups".

"We have never seen anything like this," he said of the disorder which officials report has harmed more than 200 students and 700 police officers, and prompted more than 6,600 arrests.

Nuñez later said he found it "excessive to speak of police repression of the movement", insisting that officers were only acting in response to violence and damage.

The national coordinator of the radical-left France Unbowed (LFI) party said that it had taken "several children being maimed for life for Nuñez to give up using grenades against high school students".

The prime minister has accused LFI of trying to "sow chaos" during the protests ahead of elections to select President Emmanuel Macron's successor in April.

Its leader Jean-Luc Mélenchon is currently second in the opinion polls behind Marine Le Pen of the hard-right National Rally - who on Wednesday said Macron was "always on the side of attacking the police".

The president held an emergency meeting late on Tuesday with Prime Minister Lecornu and other key ministers to find a way out of the crisis after almost a quarter of all lycées were disrupted by the day's protests - with government figures putting the number of protesters at more than 250,000.

Lecornu announced that schools should set aside half the day for students to voice their concerns, and noted on social media that an online consultation seeking their opinions had drawn 30,000 responses within a day.

But students' unions - who put the number of protesters at 450,000 - maintain a fourth round of demonstrations is planned for Thursday in Paris and other cities, and told reporters they had requested a meeting with Lecornu due to a lack of "concrete measures" outlined so far.

The union representing school leaders told FranceInfo that a solution would require "something more than simple consultation periods", while the head of the USL high school union, Ryad Rani, told French radio on Wednesday: "We are telling M. Nuñez, calm your police officers down and call for restraint."