PARIS — Fears about Europe’s debt crisis ended a rally in Europe on Thursday, pushing most share prices down as Italy’s borrowing costs rose in a debt sale.

At an Italian bond auction, the yield, or interest rate, for three-year bonds rose sharply — an indication that investors are nervous about the country’s ability to manage its debt. Spain’s yields have also been rising in recent days.

Both countries are struggling to reduce their deficits and debts while also trying to stimulate stagnant growth. Some analysts and investors fear they will need help from their European peers to keep their borrowing costs in line.

A suggestion from a member of the European Central Bank’s board on Wednesday that the bank might be willing to buy more Spanish bonds helped ease fears for a bit. Coupled with that, U.S. data indicating the world’s largest economy is growing slowly but steadily helped European stocks open higher on Thursday.