BRUSSELS?The European Union will ask Russia to be clear about its negotiations on joining the World Trade Organization (WTO) at a summit this week, the EU presidency said on Tuesday.

"That is one of the questions we will have on the table for the Russians," Swedish Foreign Minister Carl Bildt, whose country holds the EU's rotating presidency, told reporters, on the eve of the EU-Russia summit in Stockholm.

"The difficulty that we have there (with Russia) of course is the WTO and although President (Dmitry) Medvedev said a number of interesting things in his policy speech the other day I was struck by the fact that the WTO wasn't even mentioned," he said.

"Clearly that might mean something" Bildt added, noting that "the economic relationship is of course a key part of the overall relationship" between Brussels and Moscow.

In June, Russian Prime Minister Vladimir Putin announced that his country would unite with Kazakhstan and Belarus to form a customs union, and present a joint bid to become members of world trade's governing body.

That would have brought an end to Russia's long quest for WTO membership.

The WTO believes the customs union would complicate matters, and the three nations have dropped the plans to join as a group although they do intend to become members at the same time.

The EU, for its part, is now unsure about Russia's willingness to join, and is concerned that the issue could put the brakes on efforts by Brussels and Moscow to draw up a new strategic partnership to upgrade their ties.