WARSAW, Poland — Polish farmers blocked border crossings with Ukraine, spilled Ukrainian grain and burned tires on Tuesday as they intensified a nationwide protest against the import of Ukrainian foods and European Union environmental policies.

Farmers from Spain to Italy to Belgium have been protesting recently, worried that EU’s Green Deal plan to place limits on the use of chemicals and on greenhouse gas emissions will result in a reduction in production and income. They are also in revolt against competition from non-EU countries, in particular Ukraine, a large producer of agricultural goods.

Polish farmers drove their tractors through Gdansk, Krakow and other cities, honking their horns in the noisy protest. They said their action would become ever more dramatic until their demands are met. Elsewhere they blocked the entrances to highways.

They want Prime Minister Donald Tusk’s government to withdraw Poland from the Green Deal and to stop the import of agricultural imports from Ukraine. A sign on one tractor in Gdansk accused the government of caring more about Ukraine than Polish farmers. “Such a policy ruins farmers,” another sign said.

The farmers spilled Ukrainian grain from a train in Medyka, a Polish border town, sparking deep concern from Ukrainian authorities. Economy minister Yulia Svyrydenko said Kyiv hoped for a “robust response” from the European Commission.

Ukrainian authorities in the past have said border blockades threatened humanitarian material passing into the country.

“Spilling grain from a freight train onto the tracks, blocking passenger traffic is not a protest. It’s a violation of public order,” Svyrydenko wrote on X, formerly Twitter. “Given the ongoing Russian aggression, maintaining the functionality of our land borders is of utmost importance. It is crucial that the border not be held hostage to such actions.”

The protests are a growing source of tensions between Ukraine and neighbors across its Western border who support its efforts to fight off Russia’s invasion but are facing pressure from farmers. The farmers say Ukrainian grain and other food imports are damaging their livelihoods by creating a glut on the market that pushes down prices.

Ukraine’s President Volodymyr Zelenskyy singled out the protesting Polish farmers in his nightly address Monday, saying their actions indicated an “erosion of solidarity.”

“Near Kupiansk, close to the Russian border, where enemy artillery does not cease, news from the border with Poland seems outright mocking,” said Zelenskyy.

According to Zelenskyy, Ukraine exports only 5% of its grains through the Polish border. “So in reality, the situation is not about grain, but rather about politics,” he said.

In response to the protests, Ukrainian drivers started a rally near three crossing points with Poland, the Ukrainian media outlet Suspilne reported. “The blockade of Ukraine is a betrayal of European values,” a sign on one truck said.

More protests were expected Thursday in central Europe.