Buoyed by safe haven inflows, the Swiss franc hit a 27-month high against the euro last week after Switzerland's central bank kept interest rates on hold, threatening a three-year-old cap on the franc against the euro of 1.20.

The central bank said on Thursday that it had been prompted into action by the crisis in Russia which spurred demand for safe-haven currencies.

"Against this background, we were obliged to ensure the minimum exchange rate of 1.20 francs per euro by intervening on the foreign exchange market," Swiss National bank chairman Thomas Jordan said in remarks at a press conference after unveiling the rates move.

(Reporting By Caroline Copley and Katharina Bart)