Brussels said it had suspended Swiss participation in EU research and education programmes after Bern called off a deal opening market access to Croatia.
The EU's newest member, Croatia is the first victim of Swiss plans to curb immigration from other countries in the bloc, a move narrowly approved in a February 9 referendum.
"Given the circumstances and in the absence of a clear political signal to do so, upcoming negotiation rounds have been postponed until Switzerland signs" the Croatia deal, European Commission spokesman Joe Hennon yesterday told AFP.
The comment comes after the Swiss justice ministry on Saturday said the popular vote to curb immigration meant Bern could no longer sign a deal giving Croatia free access to the Swiss labour market.
Swiss voters approved the initiative to void a pact giving equal footing to EU citizens in the Swiss labour market, by a narrow 50.3 per cent.
The vote created a "new constitutional disposition ... (and) Switzerland cannot sign the accord in its current form," a justice ministry spokesman told AFP.
Switzerland's inability to sign the deal, which would have given Croatians free access to the Swiss labour market within a decade, has broader implications for the country.
Hennon pointed out that a deal enabling Switzerland to take part in the European research and development programme Horizon 2020 and another allowing Swiss students to participate in the Europe-wide Erasmus exchange programme, were also "linked to free movement of persons."
"There is a close link between Swiss association to Horizon 2020 and Erasmus+ and the protocol extending (free movement of persons) to Croatia," he wrote in an email.
His comments came amid concern that the vote in favour of the "Stop Mass Immigration" initiative, put forward by the rightwing populist Swiss People's Party (SVP), could set in motion a so-called "guillotine clause", freezing an entire package of Swiss-EU deals, including on trade.
Switzerland is not a member of the EU, but counts the bloc as its main trading partner and its economy is closely intertwined with European and global markets.
The referendum measure binds Bern to renegotiate the entire EU labour market deal within three years. The current rules stay in force in the meantime.
The Swiss government aims to present a plan on how to implement the changes before July, and to present a proposed law by the end of the year.
SVP chief Toni Brunner insisted in an interview with Schweiz am Sonntag published yesterday that Switzerland needed to move faster to put measures in place.
This was because "a new wave of massive immigration" was about to hit as the EU extends its freedom of movement to all its eastern members, he said.
