Protesters tried to tear down the barriers erected in front of parliament - a few blocks from where the summit was taking place - but police pushed them back with water hoses. Police also fired teargas.

A local official said a statue on the square where farmers were gathered near the parliament with their tractors was damaged.

Major thoroughfares in Brussels, the heart of the European Union, were blocked by around 1,300 tractors, according to a police estimate. Farmers from Italy, Spain and other European countries also took part in the protests.

Security personnel in riot gear stood guard behind barriers where the leaders were meeting at European Council headquarters.

Farmers say they are not being paid enough, are choked by taxes and green rules and face unfair competition from abroad.

EU ELECTIONS

The protests across Europe come ahead of European Parliament elections in June in which the far right, for whom farmers represent a growing constituency, is seen making gains.

"You know what's happening: European elections are coming and politicians are super nervous and also the European Commission. And I think that this is the best moment that together all the European farmers go to the street," said Jose Maria Castilla, a farmer representing the Spanish farmers' union Asaja.

One tractor displayed a banner saying "If you love the earth, support those who manage it" as farmers from Belgium and other European countries try to make themselves heard by EU leaders meeting later.

Another banner read: "No farmers, no food."

"If you see with how many people we are here today, and if you see it's all over Europe, so you must have hope. We must have hope that these people see that farming is necessary. It's the food, you know," said Kevin Bertens, a farmer from just outside Brussels.

European Parliament President Roberta Metsola said: "To the farmers that are outside. We see you and we hear you."

Farmers have already secured several measures, including the bloc's executive Commission proposals to limit farm imports from Ukraine and loosen some environmental regulations on fallow lands.

In France, where farmers have been protesting for weeks, the government has dropped plans to gradually reduce subsidies on agricultural diesel and promised more aid.

But farmers say that is not enough, and protests have spread to countries including Spain and Portugal.

MERCOSUR TRADE TALKS

While the farmers' crisis is not officially on the agenda of the EU summit, it is bound to be discussed, at least on the margins.

Already, with all eyes on Viktor Orban as the other 26 EU leaders wants to convince him at the summit to join a plan to offer stable financing to Ukraine, the Hungarian Prime Minister made a point of meeting farmers overnight.

"We need to find new leaders who truly represent the interests of the people," his spokesman quoted him as saying, referring to the European Parliament elections.

"The @EU_Commission should represent the interests of European farmers against those of Ukraine, not the other way around," he quoted Orban as saying.

As he arrived at the summit, Belgian Prime Minister Alexander De Croo said farmers' grievances should be discussed.

"They offer products of high quality, we also need to make sure that they can get the right price for the high quality products that they provide," he said.

Meanwhile, Irish Prime Minister Leo Varadkar echoed French President Emmanuel Macron's opposition to signing a trade deal with the Mercosur group of South American countries in its current form - another key demand for farmers.

In France, where farmers stepped up protests at the start of the week, the impact of dozens of blockades is starting to be felt, said Eric Hemar, the head of a federation of transport and logistics employers.

"We did a poll among our federation members: all transport firms are impacted (by the farmers' protest) and have lost over the past 10 days about 30% of their revenue, because we are not able to deliver on time or with delays," he told franceinfo broadcaster.