MOSCOW, June 24 (RIA Novosti) - The issue of Russia's accession to the World Trade Organization (WTO) as a trilateral customs union member alongside Belarus and Kazakhstan remains unclear, the WTO head said on Wednesday.

Russia, Belarus and Kazakhstan announced plans earlier in June to join the WTO as a single customs union.

Speaking on the sidelines of a meeting of the Organization for Economic Cooperation and Development (OECD) in Paris, Pascal Lamy said he was "perplexed."

"WTO members are still unclear as to what the next steps would be," he said.

Russia is the world's only major economy still outside the WTO. Consent from all 153 WTO members is necessary for a state to join the organization.

To date, Russia has completed mandatory bilateral negotiations with 60 countries, but has yet to synchronize positions on several issues, including agriculture, export duties for timber, and regulation of some state-controlled companies.

Russia has been negotiating its entry into the WTO for more than 15 years.