Rome, March 27 - The average interest rate on Italian 10-year bonds fell at an auction on Wednesday but a separate sale of five-year bonds saw the rate rise. Italian bonds have been under pressure recently in part because of the political gridlock Italy faces after last month's inconclusive election and because of concerns raised on in the international markets by the situation in Cyprus. Before Wednesday's auctions the spread between 10-year Italian bonds and the German equivalent shot up 21 basis points to 442. The spread, a key indicator of Italy's borrowing costs and of investor confidence in the country, was stable at 443 basis points at 4.57% after the sales. In the first auction on Wednesday, the Treasury sold three billion euros' worth of 10-year bonds at an average interest rate of 4.66%, down from 4.83% at a sale last month. But the rate on five-year BTP bonds, of which the Treasury sold 3.91 billion euros' worth, climbed to 3.65%, up from 3.59% last time.