The President of the European Commission, José Manuel Barroso, has said Turkey should be offered full membership of the European Union, and not a half-way house.
He was speaking as EU leaders gathered in Brussels for a summit at which they are expected to approve opening accession talks with Ankara.
However, many countries oppose Turkish membership while others want conditions placed on it.
Mr Barroso said that if negotiations start, it should be with full European membership in mind.
The issue of Turkey's possible EU membership is one of the most controversial items on the European political agenda.
Many member states are concerned at the country's record on human rights and democracy, but supporters of the move say the efforts made by its government should now be rewarded.
Commentators say accession talks are certain to take at least ten years.
