Speaking to reporters after the talks, Seks said he was confident that a fair solution to the problem would be found in the interests of both Ukraine and Croatia, adding that entire Europe was interested in an obstructed supply of gas to all countries.
Litvin assured the Croatian delegation by saying that Ukraine "has been, is and will be" a reliable partner.
Both officials praised the progress made in liberalising the visa regime between the two countries, particularly for tourists and business people.
Earlier in the day, Seks met Prime Minister Yuri Yekhanurov and Foreign Minister Boris Tarasyuk. His meeting with President Viktor Yushchenko was rescheduled for Tuesday, when he is also to visit the Antonov aircraft manufacturing factory.