(Bloomberg) -- Thousands protested in western France on Saturday against the construction of large water reservoirs destined for the agriculture industry, leading to violent clashes with police.

Some protesters hurled Molotov cocktails, explosives and various projectiles, the national security forces said on Twitter. Television images showed police vehicles on fire, as well as tear gas and water cannons being used to disperse the crowds in Sainte-Soline.

The prefect for the Deux-Sevres region, Emmanuelle Dubee, told reporters that the protesters numbered more than 6,000, including at least 1,000 who belonged to well-equipped, violent groups. Weapons including axes, machetes and knives were found on some people, she said.

“The ultra left and far left are extremely violent against our police officers,” Interior Minister Gerald Darmanin said on Twitter. “Unspeakable, intolerable.”

He told reporters that 24 police officers and seven protesters had been injured. Fifteen arrests were made.

The scenes are yet another headache for the French government, which has seen protests against its unpopular reform of the pension system escalate, with uncollected garbage set on fire in Paris and clashes against riot police in other major cities. Unions have called another day of strikes Tuesday as they remain determined to force President Emmanuel Macron to back down.

Read more: Macron Pension Gambit Sparks Revolt, Pushes France to the Brink

Environmental campaigners say the large reservoirs being constructed will provide irrigation for the agriculture industry at the expense of the water table and aggravate droughts in surrounding areas.

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