Dutch police opened fire on tractor-riding farmers who were protesting a government climate proposal late Tuesday in the north of the Netherlands.

For weeks now, Dutch farmers have organized a nationwide protest against plans to cut nitrogen oxide emissions from farm animal manure and the use of ammonia in fertilizer in half by 2030. Government officials say the plan is necessary to reduce "harmful" pollutants, but the farmers are complaining that the government's standards would destroy their livelihoods.

As part of their demonstrations against the government, farmers have used tractors to block highways and cut off supermarket distribution centers, Reuters reported.

On Tuesday, police said they fired warning shots and arrested several people after some of the protesters drove their tractors toward officers at a highway entry lane in Friesland, according to German public broadcaster Deutsche Welle.

But the protesters have contested the police account, claiming there was no threat to the officers.

Videos posted to social media appear to show Dutch police firing their weapons at a farmer driving a tractor.

\u201cDutch police shot at unarmed and peaceful farmers protesting to have their land and livelihoods returned \n\nThey\u2019ll kill farmers! This is where we are headed. Be ready \u201d

— nobody \ud83c\uddfa\ud83c\uddf8 (@nobody \ud83c\uddfa\ud83c\uddf8) 1657134746

Local media reports said the Dutch farmers' interest group LTO demanded an investigation into the incident. The police union ACP said the shooting was an incidental event that would not escalate an already tense confrontation between the government and the protesters.

Friesland police said Wednesday that no one was injured by the warning shots. An investigation into the matter has been opened because shots were fired, according to the Associated Press.

The farmers' blockade of grocery distribution centers comes days after approximately 40,000 farmers in the central Netherlands formed a tractor convoy and interrupted traffic around the country. Some farmers have set hay bales ablaze alongside highways, while others have launched demonstrations in local town and city halls, including the Hague.

Protesters say that farmers are being unfairly targeted by the government while other industries such as aviation, construction, and transport are polluting more but aren't facing crippling regulations.

To meet the government's emissions target, farmers will be forced to reduce their livestock, and farms whose animals produce large amounts of ammonia will be bought up. "The honest message ... is that not all farmers can continue their business," the government said in June.

When demonstrators gathered outside the Dutch parliament building, Prime Minister Mark Rutte said the farmers have the right to protest, but must obey the law.

“Freedom of speech and the right to demonstrate are a vital part of our democratic society, and I will always defend them," Rutte said. "But ... it is not acceptable to create dangerous situations, it is not acceptable to intimidate officials, we will never accept that.”