Small groups tried to tear down the barriers erected in front of parliament - a few blocks from where the summit was taking place - but police fired tear gas and sprayed water at the farmers with hoses to push them back.

A statue on the square was damaged and major thoroughfares in Brussels were blocked by around 1,300 tractors, according to a police estimate. Security personnel in riot gear stood guard behind barriers where the leaders were meeting at European Council headquarters.

"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," said Kevin Bertens, a farmer from just outside Brussels. "You need us. Help us!"

Farmers from Italy, Spain and other European countries took part in the demonstration in Brussels, as well as continuing their protests at home.

In Portugal, farmers made their way to the Spanish border at the crack of dawn to block some of the roads links between the two countries.

In France, farmers headed towards the lower house of parliament in Paris while drone footage showed a huge convoy of tractors on an motorway near Jossigny as others blocked highways around the French capital.

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

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.

While the farmers' crisis is not officially on the agenda of the EU summit, which so far has focused on aid to Ukraine, an EU diplomat said the situation with the farmers was likely to be discussed later in the day.