The European Commission has offered a 500 million euro relief package that farmers in the bloc say does little to address slumping prices due to the loss of exports to Russia.
The aid was announced on September 7 as nearly 5,000 farmers driving more than 1,000 tractors traveled to Brussels to protest, prompting an emergency meeting of the EU's Agriculture Council.
Protesters driving tractors snagged traffic for hundreds of kilometers outside the Belgian capital, Belga news agency reported.
Demonstrators threw bottles and paving stones, leading to clashes with police, who used tear gas and water cannons to disperse them and put out burning bales of hay, the agency said.
Four police officers and at least two demonstrators were reported injured, but no arrests were made, the agency said.
European Commission Vice President Jyrki Katainen called the 500 million euro package a "robust and decisive response" to farmers' demands, but farming groups continued to complain that it was not enough to make up for the sharp impact of economic sanctions on farm income.
Albert Jan Maat, president of farmers group Copa, said Russia was a top EU market. Sanctions imposed as a result of Russian aggressions in Ukraine and Russia's retaliatory food ban have led to the loss of about 5.5 billion euros of agri-food exports, the group estimated.
"This situation is not our fault, yet it is our sector that is being hit the most. EU farmers are paying the price for international politics," Maat said.
Farmers say they face a worsening cash-flow crisis. The situation is said to be especially dire in the dairy, pork, beef, fruit, and vegetable sectors.
"We are now in early September, bills have not been paid for the summer, and a lot of milk producers will not be able to see their way through the winter unless cash is put on the table immediately," said Mansel Raymond, dairy chairman at Copa.
Milk prices paid to EU farmers are down 20 percent from last year at 30 cents a liter on average. In the Baltic states, which have been worst hit by Russian sanctions, prices are even lower at around 20 cents.
The European Commission said its aid package was aimed at helping farmers with cash-flow difficulties, stabilizing markets, and improving the functioning of the supply chain.
The plan allows member states to advance some payments to farmers. The commission said it was working closely with the European Investment Bank to design financial instruments where repayments were linked to commodity prices.
The commission said there would be "particular regard to those member states which have been most affected by market developments."
The EU executive refused to raise the intervention price for dairy products, however, a move sought by farming groups and supported by France, Italy, Spain, and Portugal.
The EU had already implemented a series of support measures to help farmers cope with the Russian food ban, such as public purchases of agriculture goods and funds to help cover the costs of putting products into storage for later sales.
With reporting by Reuters, dpa, and Belga news agency