France’s unrest widened on Saturday as clashes between police and protesters spread to the countryside.
Police said Molotov cocktails were thrown at gendarmes by an “extremely violent crowd” in Sainte-Soline.
The protests over planned reservoirs came after days of nationwide violence linked to President Emmanuel Macron’s pension reforms.
“While the country is rising up to defend pensions, we will simultaneously stand up to defend water,” organisers in Sainte-Soline said.
In Paris, a separate march took aim at an immigration law being drawn up by Interior Minister Gerald Darmanin.
There were further protests against the pension bill as unions prepared for another day of strikes on Tuesday.
The angry public mood has forced the postponement of a state visit by Britain’s King Charles III next week.
A former French ambassador to Britain said a state dinner at Versailles would “not have given a good image” at a time of worker unrest.
Sylvie Bermann told BBC Radio 4’s Today programme it was a “real frustration” to delay a trip meant to display a new start in UK-France relations.
Mr Macron was further criticised after TV viewers spotted him appearing to remove an expensive watch during an interview.
In Sainte-Soline, riot police faced the protesters who are opposing new reservoirs for the farming industry.
They argue that the “mega-basins” would siphon water away from locals, amid fears of a summer drought in Europe.
Protest organisers claimed 25,000 people were involved in a long procession that led to clashes breaking out around the construction site.
Some of the 3,000 police on site fired tear gas and water cannon after projectiles and improvised explosives were thrown by protesters.
At least eleven people were detained, AFP reported. Police were said to have seized weapons including explosives, meat knives and pétanque balls.
Mr Darmanin alleged that the “ultra left and extreme right” were behind the violence.
He said the scenes in Sainte-Soline were “unspeakable, unacceptable … nobody should tolerate this”.
Mr Macron has said he will not yield to violence over the pension bill as unions vow to continue their struggle.
The bill to raise France’s retirement age from 62 to 64 was forced through by decree after Mr Macron’s party failed to win a majority.
His government survived a confidence vote but the move has unleashed massive protests in Paris and strikes across the country.
In another violent incident, an elite gendarme was shot dead in the French territory of Guyana during an operation against illegal gold mining, officials said on Saturday.
Mr Macron said he “saluted the courage and commitment” of the officer, identified as Arnaud Blanc.