The European Commission has recommended that some elements of talks with Turkey about its hopes of joining the EU should be frozen.
Turkey's bid has polarised opinion in Europe
The recommendations follow the breakdown of talks over the divided island of Cyprus.
Turkey's refusal to recognise the Cypriot government has become an obstacle to Turkey's membership hopes.
Turkish television channels quoted Prime Minister Tayyip Erdogan as saying the recommendation was "unacceptable".
After Finland said on Monday that talks over the Cyprus issue were deadlocked, the European Commission brought forward an announcement it was due to make next week.
It said eight of the 35 areas of negotiation between the EU and Turkey should be suspended.
It also said no area of negotiation should be declared complete until the Cyprus situation is resolved.
This was a much tougher conclusion than was expected and could act as a major disincentive for Turkey to resume any negotiations, says the BBC's Jonny Dymond in Brussels.
Final decision awaited
"There is a unanimous decision by the member states to conduct accession negotiations with Turkey... Turkey has undoubtedly made progress. But it has still not implemented all obligations it has agreed to," EU Commission President Jose Manuel Barroso said in a statement.
The EU insists that Turkey fulfils its commitment to open its ports to traffic from Cyprus, but Turkey says it will not do so until the EU eases its embargo on Turkish-controlled northern Cyprus.
Cyprus has been divided since 1974, when Turkish troops invaded to counter a Greek Cypriot coup backed by the military junta ruling Greece at the time.
The final decision on whether to suspend negotiations will be made by EU foreign ministers, or by heads of government when they meet in mid-December.
Some countries want to go further than the European Commission recommends and suspend negotiations in more areas, says our correspondent in Brussels.
Suspending some chapters would not mean Turkey's application would be halted altogether, but could make it difficult to get full negotiations back on track, he adds.
Finnish Prime Minister Matti Vanhanen will visit Turkey on Friday to meet his Turkish counterpart Mr Erdogan, in a last-ditch effort to reach a breakthrough.