"In the absence of a common agreement, the opening of accession negotiations is postponed,"
Asselborn said at a news conference, reading out conclusions of the EU Council of Ministers.
The Council adopted a negotiating framework for Croatia, under which talks will open as soon as the necessary conditions are met.
According to the conclusions adopted at today's meeting, an intergovernmental bilateral conference will be convened by joint agreement as soon as the Council is able to establish that Croatia is fully cooperating with the International Criminal Tribunal for the former Yugoslavia (ICTY).
Asselborn said that the talks could start already next month, when the next Council session is to be held, if Croatia met the set condition by that time.
Neither the EU nor the The Hague nor any EU member holds the key to opening the talks, the key is Croatia and its full cooperation with the ICTY, he added.
Asselborn said he was confident that the Croatian government would make additional efforts to meet the set condition after today's decision.
European Enlargement Commissioner Olli Rehn said the Council's decision would send a signal to Western Balkan countries that the door to the EU was open to them as soon as they met the necessary conditions.
Rehn stressed that the EU considered the rule of law and the fulfilment of international obligations very important.
The negotiating framework means that the EU is ready to open the talks as soon as Croatia is ready. Croatia's future is in the European family, Rehn said.
The Council's conclusions make no direct mention of the remaining indictee who must be located and transferred to The Hague, as stated previously in the European Council's decision in December, but they do recall those conclusions.
The Council has reiterated the importance of the full cooperation with the ICTY of all western Balkan countries; this is an important request for the continuation of their integration with the EU. The Council has also cited the conclusions of the European Council of December 2004, read the conclusions.
Asked why the conclusions made no mention of the runaway General Ante Gotovina, Asselborn said that the December conclusions did not state that the condition for the start of entry talks was Gotovina's transfer to The Hague, but full cooperation with the ICTY.