U.S. stock index futures pared gains on Friday ahead of the U.S. government's April payrolls report, as nervous investors braced for volatility in the markets following Thursday's dramatic intraday bounce in shares.

S&P 500 futures rose 3.1 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures gained 35 points and Nasdaq 100 futures added 10.25 points.

U.S. stocks tumbled 9 percent within the last two hours of trading on Thursday before clawing back some losses as a suspected trading error and fears of a new credit crunch in Europe threw markets into disarray.

(Editing by Padraic Cassidy)