UPDATE 1-New U.S. CFTC head says he will be tough cop, tweak rules
July 31, 2014 at 12:31 PM EDT
WASHINGTON, July 31 (Reuters) - The new head of the U.S. derivatives regulator on Thursday pledged he would be a tough cop now that the agency has largely finished a raft of new rules to oversee the $710 trillion global swaps market.