** Shares of U.S. credit card firms fall in premarket trading as China imposes additional tariff on U.S. goods in escalating trade war

** Payment firms face the risk of weak credit card spending, as consumer confidence is expected to take a hit from economic uncertainties stoked by the trade war

** American Express Co down <AXP.N> 4.1%, Visa Inc falls <V.N> 2.6% and Mastercard Inc slips <MA.N> 2.7%

** The selloff comes after AXP fell 10% on Thursday, MA fell 3.1% and V fell 2%

(Reporting by Ateev Bhandari in Bengaluru)

((Ateev.Bhandari@thomsonreuters.com; ))