A protester with trauma to the head was fighting for his life on Sunday after clashes with police during a demonstration over water storage facilities in France, a prosecutor confirmed.

Organizers of the protest in the southwestern village of Sainte-Soline on Saturday had previously said that one demonstrator was gravely wounded.

According to the latest figures from the prosecutor's office early afternoon on Sunday, seven protesters were injured, including three who had to be taken to hospital.

Twenty-nine police officers also sustained injuries, two of them badly enough that they had to be hospitalized.

Prosecutor Julien Wattebled indicated a 30-year-old man with head trauma was fighting for his life after being among the three protesters admitted for emergency treatment.

A special inquiry had been opened "to determine the exact nature" of the injuries of these three people and "the circumstances in which" they received them, Wattebled confirmed.

The other two badly injured demonstrators were a 19-year-old woman with facial trauma and a 27-year-old man with a broken leg.

Campaigners in Sainte-Soline were trying to stop the construction of giant water "basins" to irrigate crops, which they say will distort access to water amid drought conditions.

Once they arrived at the construction site, which was defended by the police and gendarmes, clashes quickly broke out between the more radical activists and the security forces, AFP correspondents said.

Protesters threw projectiles including improvised explosives, while police responded with tear gas, water cannon, and rubber bullets.

Read more: Macron in the hot seat as hundreds injured in ongoing protests

The battle of Sainte-Soline in France is epic.

With heavy firework shelling the protestors are advancing towards the riot police concentration.

1/ pic.twitter.com/GS4C1vf5sV

— Lord Bebo (@MyLordBebo) March 25, 2023

The clashes in Sainte-Soline came after days of unrest elsewhere in France over President Emmanuel Macron's pensions reform, which forced the cancellation of a visit by Britain's King Charles III.

Outrage over Macron imposing the bill without a parliamentary vote has sparked daily clashes between protesters and police in French cities in recent days.

Hundreds of thousands of French people have since January marched against the reform, which includes raising the retirement age from 62 to 64.

Security forces have this week faced criticism for their heavy-handed tactics in dealing with the protests. On Friday, the Council of Europe warned that sporadic violence in protests "cannot justify excessive use of force."

On Saturday, local media reported that 15 investigations of police brutality against demonstrators have been opened in France amid the widespread protests.

According to BFM, investigations are centered on the use of excessive force and verbal threats by police teams against protestors.

It was further reported that three of the investigations were opened by the Paris public prosecutor, while the interior minister authorized the other 12 investigations.

Read more: Iran urges France to listen to protesters, avoid violence