WARSAW, March 13 (Reuters) - Polish farmers increased the number of trucks they let through the Dorohusk border crossing with Ukraine on Wednesday but backpedalled on a promise to unblock it completely, state news agency PAP reported on Wednesday.

Protest leader Wojciech Los told PAP that the number of trucks allowed to cross had been raised to five per hour from one or two previously. He had previously said that all trucks stuck there would be allowed through as a gesture of goodwill.

"Some of the organisers wanted this, but unfortunately there was no full agreement among the protesters and we finally agreed that we would increase the number of trucks allowed through to five per hour," he said

Farmers in Poland and across the European Union have been calling for changes to restrictions placed on them by the EU's Green Deal plan to tackle climate change, and for the re-imposition of customs duties on imports of agricultural products from Ukraine that were waived after Russia's invasion in 2022.

Elsewhere, Polish farmers said they would block their country's border crossing with Slovakia at Chyzne from Friday until the end of March, PAP reported. They plan to let one truck through per hour, according to the agency.

A protest was also under way on Wednesday at the Barwinek crossing on the Polish-Slovakian border, where farmers were checking the contents of every truck, causing traffic jams, PAP reported.

The farmers told the website Wp.pl on Tuesday this was because they had discovered that Ukrainian and Russian agricultural products were entering Poland via Slovakia, which is also an EU state.

Last Saturday, Polish Prime Minister Donald Tusk pledged to reduce a grain surplus on the domestic market at talks with farmers, but union leaders said they would press on with their protests.