A day after the Swiss voted to extend a labour accord to the new European Union states, Brussels is tight-lipped about whether Switzerland should join the EU.
The European Commissioner for External Relations, Benita Ferrero-Waldner, said it was up to the Swiss to decide whether to continue with the bilateral approach or to become an EU member.
She is due to meet Swiss Foreign Minister Micheline Calmy-Rey in Strasbourg on Tuesday.
Diana Wallis, who heads the EU parliamentary delegation responsible for Swiss relations, told swissinfo that the "unusual and complex" system of bilateral agreements had run its course.
As an alternative to membership, Switzerland has taken the "bilateral" route, concluding 16 agreements with Brussels in two separate rounds of negotiations.
After voters twice this year approved closer ties with the EU, attention is turning to the question of what Switzerland should do with its membership application, which has been on ice in Brussels since 1992.
Swiss ministers are to discuss that question next month. In the meantime, the EU is making it clear that any decision about membership is one for the Swiss to initiate.
Wallis, who is to meet Swiss parliamentarians in Bern on Tuesday to discuss the ramifications of Sunday's vote, said the issue of membership needed to be "carefully considered".
No more bilaterals
"My personal view is that Switzerland should look at full membership," Wallis told swissinfo. "I don't think this unusual and complex relationship will work in the long term. I would not want to see a third round of bilateral agreements."
Wallis added that talk of bringing all the bilateral agreements under one umbrella should not be interpreted as a sign of real progress, but rather as an administrative tidy-up of existing arrangements.
European Commissioner for Employment, Social Affairs and Equal Opportunities, Vladimir Spidla, echoed Ferrero-Waldner when speaking to swissinfo in Brussels.
"The question of EU membership is for the Swiss people to decide," he said. "They have shown with the referendum that they have trust in the bilateral relationship up to now.
Open to discussion
"The EU has never imposed on anyone to join. We are open to discussion, but it is up to the Swiss to initiate."
Meanwhile, business continues as usual at the Swiss Mission to the EU in Brussels.
Preparatory discussions are being opened on four new areas: opening up the electricity market Europe-wide, participation in the European GPS system Galileo, cooperating with the European centre for disease prevention and recognising certificates of origin for food products.
The mission insists that these negotiations do not represent another set of bilaterals because they are being negotiated separately rather than as part of a package.
But the mission's boss Bernhard Marfurt believes the positive referendum result has enhanced Switzerland's standing with the EU. "Our partnership has been strengthened and we have a solid basis for future cooperation," he told swissinfo.
swissinfo, Matthew Allen in Brussels
Switzerland and the EU have concluded 16 bilateral accords.
Sunday's vote on extending an existing free movement of people accord to the ten new EU member states was the seventh nationwide ballot on relations with Brussels in 13 years.
A request for full EU membership was frozen in the wake of Swiss voters' rejection of the European Economic Area treaty in 1992.