Kyiv sent a formal note regarding what it said were Polish trade restrictions on importing agricultural products. The EU agreed in principle on an arrangement to get some produce out through neighboring countries.

Ukraine has protested what it described as "categorically unacceptable" bans against the transit of its agricultural produce through neighboring Poland, as the war continues to challenge produce routes out of the country.

The Foreign Ministry said on Saturday that it sent a formal note to the Polish and European Union representatives in the country a day before regarding the bans.

Poland and other Ukrainian neighbors have recently imposed temporary trade barriers on grains and other goods. The bans followed protests by local farming after a drop in the prices of local produce.

In the note, the Ukrainian ministry argued that the restrictions fail to comply with the Association Agreement between Kyiv and the EU, as well as the EU Single Market norms.

"There are full legal grounds for the immediate resumption of exports of Ukrainian agricultural goods to Poland, Romania, Hungary, Slovakia and Bulgaria, as well as the continuation of unhindered exports to other EU member states," it continued.

Meanwhile on Friday, the EU announced reaching an agreement "in principle" with Ukraine's neighbors Bulgaria, Hungary, Poland, Romania and Slovakia regarding the passage of produce.

The deal involves the withdrawal of any unilateral measures the five countries have taken against Ukrainian produce, in exchange for a €100m (approximately $111.27) support package for the affected farmers in the countries.

The deal also would involve "exceptional safeguard measures" for the transit of Ukrainian wheat, maize, rapeseed and sunflower seed.

"We have acted to address concerns of both farmers in neighbouring EU countries and Ukraine," said European Commission Vice-President Valdis Dombrovskis on Twitter.

Kyiv welcomed the deal, saying it would mostly benefit Middle Eastern and African countries that rely on its food exports.

Grain exports are a vital source of revenue for Ukraine, which is among the world's top suppliers.

According to the European Commission, Ukraine accounts for 10% of the world wheat market, 15% of the corn market, and 13% of the barley market. With more than 50% of world trade, it is also the main player on the sunflower oil market.

The Russian invasion, however, has largely impacted Kyiv's ability to export its produce via the Black Sea, despite the UN-brokered grain deal with Russia. This made the country resort to using its neighbors as outlets for its produce.