Demonstrators on the AP-7 motorway began gathering at Pontos some 40 kilometres (25 miles) from the French border, on Monday evening and started blocking the road shortly after midnight, cutting it off in both directions, protesters said.

They also blocked the A2 motorway linking Madrid and Barcelona as part of a string of protests over what they say is unfair competition from outside the EU.

They say such products “do not have to meet the same criteria” that EU member states are required to apply, and they also want Brussels to reduce the red tape, according to a statement from Unio de Pagesos, one of the farmers’ unions behind the protest.

Farmers across Europe have been protesting for weeks over what they say are excessively restrictive environmental rules, competition from cheap imports from outside the European Union and low incomes.

Since the start of February, farmers have been mobilising across Spain.

Catalan farmers flexed their muscles earlier this month when a thousand tractors converged on Barcelona.

Thousands marched through Madrid on Monday following a demonstration five days earlier in which 500 tractors trundled into town.

Brussels was also paralysed by protesters on Monday as some 900 tractors took to the streets of the European quarter where EU ministers were huddled to try to streamline rules and reduce the red tape that is fuelling protests across the bloc.

Furious farmers lobbed eggs, burnt tyres and sprayed manure at riot police who hit back with water cannon and teargas.

Since the start of the protests in Spain, unions and protest organisers have met several times with Agriculture Minister Luis Planas who pledged to ask the EU to simplify its common agricultural policy (CAP).

He also agreed to ask Brussels to ensure mirror clauses — which ensure imports respect EU agricultural rules — are imposed on pesticides, and to improve Spain’s agri-foodchain legislation so producers are not forced to sell at a loss.

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