Turkey's EU membership talks are to be partly frozen after European foreign ministers agreed last night on a punishment for Ankara's failure to open up ports and airports to trade with Cyprus.

The compromise deal puts the brakes on membership talks by placing a quarter of Turkey's EU talks in the deep-freeze.

But it averts the possibility of a clash among EU heads of government who meet on Thursday at a summit in Brussels.

The decision is a blow to Turkey, which had hoped to stave off the prospect of a partial freeze of negotiations with an late offer to open a port and an airport to Cypriot commerce. That was deemed insufficient because Ankara's plan was not unconditional but part of a package.

In the end, EU member states rallied around a compromise proposal from the European Commission which will freeze eight of the 35 chapters - policy areas - into which Turkey's EU negotiations are divided. The areas covered include trade, financial services and transport.

Under yesterday's agreement the Commission will monitor Ankara's progress on opening ports to Cyprus in 2007, 2008 and 2009 "as appropriate". That formulation was also a compromise, falling short of a firm commitment originally demanded by Paris and Berlin, to re-examine the issue on a specific date.

Both supporters of Turkish EU membership and sceptics claimed victory. The UK, which has championed Ankara's cause and originally argued for only three chapters to be frozen, said the deal kept alive Ankara's hopes of joining the EU.

Margaret Beckett, the Foreign Secretary, said: "There is no train crash, the train is firmly on the tracks. Yes, eight chapters have been frozen but 27 out of 35 are not and there is every prospect that things will work steadily and effectively to make Turkey, in the fullness of time, a member of the European Union."

Austria, one of the most forthright critics of Turkish accession, took the opposite point of view. Its Foreign Minister, Ursula Plassnik said: "Eight central negotiating areas are going to be put into the deep freeze", adding: Turkey can count on "no guarantees, nothing is automatic." The Spanish Foreign Minister Miguel Angel Moratinos added: "It's important to send this double signal that, on the one hand there should be no train crash ... but there should be a slowdown."

All eyes will now be on Ankara's reaction. The Turkish government has been under pressure from public opinion to quit the talks. But Turkey may wait until next year to assess whether there is any progress in the areas of the negotiation which are still officially active.

With Cyprus now inside the EU, Ankara has been under mounting pressure to extend to the Nicosia government a customs union that applies to other European countries and open up its ports. But Turkey, which does not recognise the Greek Cypriot government, has said it will start doing so only if the EU honours a political promise it made in 2004 to end the economic isolation of Turkish-dominated northern Cyprus.

That pledge was made after the northern Cypriots voted to accept a United Nations plan to reunite the island. But, with the officially-recognised government of Cyprus now inside the EU, Nicosia has blocked progress on easing the plight of the northern Cypriots.

Last week, Ankara proposed opening up one seaport and an airport to Cypriot trade but only as part of a package of measures. Those measures would have seen a reciprocal deal covering a northern Cypriot port and airport. Barring a unilateral opening by Ankara, the issue is now unlikely to go to this week's summit.

Turkey's application to join the EU has divided its 25 members. Countries such as Austria, Germany and France know that domestic public opinion is firmly against Turkish accession.

Others, such as the UK, argue that it is vital for the EU to embrace the large, mostly Muslim, nation to send a message to the Islamic world. While Turkey is relatively poor, it is also a key energy hub and has military capabilities which would boost the EU's fledgling defence initiative.