Thousands of Spanish farmers on tractors blocked main roads and some city streets on Friday in a fourth consecutive day of protest against European Union agriculture policies.

They are also demanding measures to offset production cost increases, reduced profits and competition from non-EU countries.

The actions follow similar protests in France, Poland, Greece and other EU member nations in recent weeks. Farmers complain that the 27-nation bloc’s environmental and other policies are a financial burden and make their products more expensive than foreign imports.

The European Commission, the EU’s executive arm, has made some concessions to farmers over the last few weeks, including shelving plans to halve the use of pesticides and other dangerous substances.

In Spain, farmers maintain that a law aimed at guaranteeing wholesale major supermarket buyers pay fair prices for their goods is not being enforced while consumer prices soar.

Friday’s protests centred around the northern cities of Oviedo, Pamplona and Zaragoza, with tractors clogging several city streets and commuter roads. In many places, farmers had kept their protests going overnight.

A group not affiliated with Spain’s three main farming organisations has called for farmers to move on Madrid at midnight for a Saturday protest near the headquarters of Prime Minister Pedro Sanchez’s Socialist party.

The demonstrations are expected to continue over the coming weeks with a major protest being organised in the capital for February 21st.

Several Spanish media reports have linked many of the protests to conservative and right-wing groups.

Police said 20 people have been arrested during this week’s demonstrations.