Cooperation of Ukraine with Customs Union in ``3+1'' format preserves its urgency --
Cooperation of Ukraine with the Customs Union that consists of the Russian Federation, Belarus and Kazakhstan in ``3+1'' format preserves its urgency.
Ukraine may join a customs union formed by its ex-Soviet peers Russia, Kazakhstan and Belarus, the Ukrainian president said Friday, casting doubts on Kiev's hopes of a free-trade pact with the European Union.