Ukraine's accession to the Convention on Common Transit and the Convention on the simplification of formalities in trade in goods
From this date, transit operations in which Ukraine appears as the country of origin, circulation or destination of the goods must be duly guaranteed, and it is the obligation of the holder of the transit regime to constitute a guarantee in order to ensure payment of the amount of import duties corresponding to the customs debt and other charges that may arise with respect to the goods included in the transit regime. The guarantee must contain the identification (surname and first name or company name and full address) of the guarantor's representative in Ukraine.
In the case of having a previously granted comprehensive guarantee authorisation or guarantee waiver to carry out transit operations, if you wish for said authorisation to extend its effects to operations to be carried out with Ukraine, you must request a modification of said authorisation in order to include Ukraine in the geographical scope of validity of the common transit countries (Box 1/5 Comprehensive guarantee authorisation/guarantee waiver).
The guarantees previously provided to secure transit operations shall be valid for carrying out operations with Ukraine provided that the necessary adaptations are made to the text of the guarantees to reflect the extension of their effects to said operations.
In the attached link you will find the information published on this subject by the Directorate General for Taxation and Customs Union (DGTAXUD) of the European Commission.