Europe's farmers have ramped up protests against EU measures and rising prices, with roads blocked in Poland, Hungary, Spain and Belgium.

In western Poland some 1,400 tractors took part in a protest in Poznan and roads were blocked across the country.

For the fourth day in a row, tractors cut off traffic in several Spanish regions, hoping to enter cities including Toledo and Zaragoza.

The protests have galvanised farmers across the continent.

However, their grievances vary widely.

Farmers in Poland and Hungary complain that the European Union is not doing enough to halt cheap imports from Ukraine undercutting local produce. They want the EU to restore a requirement on Ukrainian truckers to obtain a permit to work across the 27 member states.

In Poland, lines of tractors, many flying the Polish flag, appeared on roads in 256 places, blocking traffic and forcing police to arrange diversions. One of the blockades halted traffic at the Medyka border crossing west of the Ukrainian city of Lviv.

Protesters in Poznan lit flares and firecrackers and a barrel of waste was poured on to the street. Organisers said some 6,000 farmers had converged on the city.

Many of the farmers bore banners saying no to the EU's Green Deal, aimed at bringing down greenhouse gas emissions.

The atmosphere was more febrile in the city of Bydgoszcz where a pile of tyres and straw were set alight, as well as an EU flag. A group of protestors tried to force their way into a local authority building but the police used pepper spray to stop them.

The new agriculture minister, Czeslaw Siekierski, met protesting farmers in Przyborowice, northwest of Warsaw: "Farmers are protesting because they are in a difficult situation. My duty, as agriculture minister, is to be here today with the farmers to talk to them".

Earlier this week the European Commission recommended that net emissions should be slashed by 90% by 2040 compared with 2015 levels, but scrapped its Green Deal plan to halve pesticide use across the EU. Farmers have complained that cutting pesticides will harm their crops and jeopardise food production.

Hundreds of Hungarian farmers converged in their tractors on the main border-crossing with Ukraine at Zahony, on Friday, joining the Europe-wide protests for the first time.

Organisers said they were protesting against cheap Ukrainian imports which were undermining Hungarian markets, and also in solidarity with farmers elsewhere in Europe.

"According to my calculations, the average loss this year to a farmer for the wheat we planted last September will be about €300 per hectare," Hungarian agriculture expert Csaba Juhasz told the BBC. "That's taking any subsidies or support we receive into account."

He says medium-sized farms of 100-400 hectares have been worst hit.

Hungary's farmers share many of the concerns of their counterparts elsewhere, such as high fertiliser prices and cheap imports of Ukrainian grain, dairy produce, eggs and meat.

But they have the full support of Prime Minister Viktor Orban, who met protesting farmers at last week's EU summit and accused Brussels of prioritising Ukrainian farmers ahead of the rest of Europe.

An estimated 600 farmers headed to the Belgian city of Genk, where EU ministers were holding an industry summit.

Politicians should be supporting them, dairy farmer Wim Kwanten told Flemish broadcaster VRT, but instead they were "being held hostage by climate and environment targets - we want a level playing field for all European farmers".

In Spain, farmers shut down roads for a fourth day in several areas, snarling up traffic in big cities such as Bilbao where 100 tractors headed to the centre in columns.

Residents in Pamplona woke up to find dozens of tractors parked in two columns in the city centre, while a motorway in Toledo was brought to a standstill and hundreds of tractors blocked access to the heart of the historic city.

Agriculture unions in the Basque country complained about EU policies and minister Luis Planas said that he respected their right to demonstrate, but urged farmers to avoid intimidation or violence.

In Greece, farmers have demanded lower electricity prices, tax-free diesel and subsidised animal feed, as well as changes to EU environment rules.

Prime Minister Kyriakos Mitsotakis is expected to meet farmers' leaders next Tuesday but the government has insisted that the roads must remain open.

The prime minister's spokesman said he was always open to dialogue, but the right of one group to protest could not be at the expense of others.

Farmers in Italy were heading for the Sanremo song festival on Friday where they planned to read a statement out on stage.

A parade of tractors were due to drive around Rome's motorway ring road on Friday evening, but a large tractor rally in the central Piazza San Giovanni was cancelled so as not to annoy the public.

A symbolic convoy of four tractors drove past the Colosseum shortly before the big agriculture organisations met Prime Minister Giorgia Meloni, who has criticised "ideological" EU rules.

Farmers are also angry about an income tax break that was scrapped as part of this year's budget. Ms Meloni said during the meeting that instead of being scrapped it would be better targeted to help those on the lowest farming incomes, Ansa news agency reported.

Agriculture Minister Francesco Lollobrigida insisted his government was on the same side as the farmers on nine out of 10 points. (BBC)

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