European stocks were mixed Tuesday amid rising trade frictions between the United States and China. But the Swiss franc continues to strengthen as the conflict escalates.

The German DAX index was up 0.5% in morning trade in Frankfurt, while the FTSE 100 in London was flat. France's CAC 40 advanced 0.7%.

The Swiss franc — a safe haven in times of global tumult — hit its highest level against the euro in two years. As of mid morning, one euro bought 1.09 Swiss francs, breaking through what the markets consider a physiologically important mark of 1.10 Swiss francs.