The euro has fallen by more than a cent against the dollar, dropping below $1.30 after the US markets opened lower.
It was unclear exactly what the trigger was. Italian bond yields, having fallen after the country's successful debt auction earlier today, are now rising.
The difference between the benchmark German ten-year bond yields has also widened, with investors buying German government debt.
The euro hit 1.2970 at one stage, having been trading at 1.3080 earlier today.
Italian ten-year yields were just touching 7% according to Tradeweb figures reported by Reuters, up 2 basis points on the day. German ten-year yields were down 2 basis points.
The Dow Jones Industrial Average is down 36 points, a 0.3% fall, meanwhile. The FTSE 100 has been pegged back, too - up by just 16 points now, or 0.3%.
