Italy's 10-year bond yield has climbed back above six per cent as tension returned to the markets after the ECB said it did not consider further anti-crisis measures at a monthly meeting.
Shortly after 1400 GMT on Thursday (midnight AEST) the rate of return asked by investors to hold Italian 10-year bonds rose to 6.016 per cent from 5.755 per cent at Wednesday's close.
It had been below six per cent since last week's EU summit, when leaders took steps to confront the crisis.
The yield on Spanish 10-year bonds rose to 6.786 per cent from 6.775 per cent on the secondary sovereign debt market.
Earlier in the day Spain had to pay sharply higher yields in an auction of new bonds on the markets.
Despite raising the full amount it had aimed for, on the 10-year bonds Spain had to offer investors an average return of 6.430 per cent, up from 6.044 per cent in the last comparable sale on June 7.