Russian Ambassador to Ukraine Mikhail Zurabov said the Customs Union could advance terms to Ukraine for acquiring observer status in this organization.

"The most appropriate and optimal option within the framework of the Eurasian Economic Commission and Customs Union structures, would be for the Customs Union to advance certain demands, including to observer countries," Zurabov said at a press briefing in Kyiv on Monday.

This means, he said, that if a country decides to become an observer in the Customs Union, it will have to comply with certain requirements to be set by the member-states.

"Such an approach would be much more progressive than signing a memorandum with Ukraine on its joining the Customs Union as an observer," the Russian ambassador said.

The Customs Union currently comprises Russia, Belarus and Kazakhstan.