It is more reasonable for Ukraine to maintain an opportunity to independently sign agreements on free trade with various other countries, while not passing sovereignty in this issue to the European Commission and Eurasian Commission, according to WTO ex-Director General (2005-2013) Pascal Lamy.

Delivering a speech at the Yalta international meeting on Saturday, he said that there are two main models: passing sovereignty to a transnational agency, like the European Union or Customs Union, or without passing it, like Mexico, South Korea, Switzerland, and Canada do.

"You maintain sovereignty of your foreign trade and just correct definite indicators between the various states. It seems to me that this option is more suitable for your country," the expert said.

He gave three arguments to support his position. Firstly, Ukraine as a country with great land resources, and in terms of cheap labor force and land reserves has considerable differences, both from the EU and the Customs Union.

Secondly, as Lamy said, the volumes of foreign trade of Ukraine with the EU and Customs Union are nearly equal, while the structure of imports and exports varies a lot and probably should remain varied and mutually complementary.

The third reason he said was the geographically profitable position of Ukraine for trade with the EU as well as with the Customs Union.

Lamy said that some standards of the EU and Customs Union in future could function under the aegis of a framework agreement that is meant to ensure the merging of two systems, including spheres that are important for Ukraine such as trading in energy resources.

"But now Ukraine should follow the example of Mexico, which has an agreement on free trade area with the United States, Canada, as well as with the EU, a number of Latin American countries, and now with some Asian countries," WTO ex-head said.

The well-known economist Nouriel Roubini supported Lamy's opinion.

"Talking about choice, Pascal was right: you shouldn’t choose one option or another [EU or Customs Union]. There is a third option: a free trade area with a number of countries. If you're locked in the Customs Union, you won't be able to sign free trade area agreements, but the Association Agreement with the EU gives such an opportunity," Roubini said.

He said that in the case of accession to the Customs Union, instability in Ukraine could even worsen.