"There is no doubt that some member states are trying to erode our political and juridicial position on the adhesion process but that sort of attitude is wrong and doesn't reflect a responsible approach," Turkish Foreign Minister Ali Babacan told a press conference in Brussels.

"Provocation" from some nations would not deflect it from its goal, he added, after Turkey officially opened talks on another two of the 35 policy chapters which must be successfully negotiated prior to membership.

"If the goal behind these provocations is to get Turkey to renounce its principles and ideals it won't work," he said, without mentioning any member states by name.

France has been leading the lobby to keep Turkey out of the European Union.

French President Nicolas Sarkozy is a staunch opponent of Ankara's EU bid and advocates a special partnership with largely Muslim Turkey rather than full membership.

The French stance is largely backed by Cyprus, which Turkey refuses to trade with, and Austria.

Britain, Sweden and most of the newer EU states are championing future Turkish membership.

Wednesday's deal brings to six the total number of chapters Turkey has opened since formal accession talks began in October 2005.

Eight others were frozen a year ago because of Ankara's refusal to open its ports and airports to vessels and aircraft from EU member state Cyprus, with which it has a long-standing dispute over the Turkish-occupied northern third of the divided island.

Turkey's talks are expected to last at least a decade, with no guarantee of membership at the end of it all.

Croatia, which began membership talks at the same time as Turkey, is in pole position to become the 28th EU member state.

Its progress has been appreciably faster and the opening of two more policy chapters in its own talks on Wednesday brings its total to 16 of the 35.

The chapters on "Trans-European Networks" and "Consumer and Health Protection" were officially opened in the presence of Turkish and EU officials.

The move was made possible by the creation last week of a "reflection group" on the future of Europe. France had insisted that the committee be set up as a condition for not blocking Turkey's progress on the talks.

However Portuguese Foreign Minister Luis Amado, whose country holds the EU's rotating presidency until the end of the month, said "the adhesion process with Turkey is still totally alive".

But a poll published by the commission Tuesday showed a further erosion of support among the Turkish people for the goal of EU membership with 49 percent in favour, down from 54 percent a year ago.

"All negative perceptions of Turkey lead the Turkish population to feel that they are not wanted and that has a negative impact on the position regarding the EU," said Babacan.

Also attending the Brussels ceremony, EU Enlargement Commissioner Olli Rehn said he hoped two or three more chapters could be open during the Slovenian EU presidency in the first half of 2008.

"We have to be fair by respecting the framework of the negotiating framework of 2005 agreed by all member states," which stipulates the objective of the talks is membership, even if this is not guaranteed, he added.

To show support, European Commission chief Jose Manuel Barroso will visit Turkey "in the coming months," said Rehn.

One subject which was not raised at Wednesday's talks here were the recent Turkish attacks on Kurdish militants in northern Iraq.

On Monday the EU presidency voiced concern after the Turkish military launched air attacks on Kurdish rebel bases accross the border in Iraq, urging Ankara to exercise restraint.

"That wasn't on our talks agenda" said Amado.