The European Union's agriculture commissioner, Franz Fischler, has denied that Brussels tried to pressure Switzerland into opening talks on tax evasion and customs fraud.
Fischler's comments, made during a visit to Bern on Friday, come after the EU's foreign affairs commissioner, Chris Patten, hinted that a delay in opening talks on those issues could hold up the ratification of seven bilateral accords agreed between Switzerland and the EU.
In a letter to the Swiss foreign minister, Joseph Deiss, Patten wrote: "Any further delay could have a serious negative impact on the future course of relations in these and other areas."
He added that a new round of talks "could only benefit" the process of ratifying the accords.
Fischler, who was meeting the Swiss economics minister, Pascal Couchepin, said Brussels had no intention of linking the ratification of the accords with new talks on further bilateral agreements. He added that Brussels was firmly behind the accords.
Couchepin welcomed Fischler's comments, but said the government would be seeking further clarification from Brussels. He added that the cabinet would discuss Patten's letter when it meets next Wednesday.
The seven agreements - governing issues such as transport and the free movement of people - were approved by Swiss voters last May, but some EU states have been slow to give their backing and final ratification is now not expected before the summer.
Responding to Patten's letter on Thursday, the Swiss foreign ministry said it was entirely inappropriate for the EU to make ratification of the seven bilateral accords dependent on new negotiations.
"Any connection between the new negotiations and the on-going ratification of the bilateral accords, as suggested in this letter, is wholly unacceptable to us," said foreign ministry spokesman, Ruedi Christen.
Christen also made clear that while Switzerland was ready to discuss closer cooperation on security issues, it needed further assurances that its concerns were being taken seriously by the EU.
"We need a signal from the Council of Ministers, not just from the Commission," said Christen. "And even more importantly, all outstanding issues from the previous round of accords need to be settled."
swissinfo with agencies