In May, the EU agreed to restrict imports to Bulgaria, Hungary, Poland, Romania and Slovakia, seeking to protect farmers there who blamed the imports for a slump in prices on local markets.
The measures allowed the products to keep transiting through the five countries, but stopped them being sold on the local market.
Poland, Hungary and Slovakia immediately announced they would defy the move.
The issue is particularly sensitive in Poland, where elections take place next month. The existing populist right-wing government of the Law and Justice party has strong support in farming regions.
Kyiv responded to warnings by Poland, Hungary and Slovakia by announcing that it would lodge a complaint with the World Trade Organization (WTO).
With Agence France-Presse
