RPT-INSIGHT-In taking economic war to Islamic State, U.S. developing new tools
November 24, 2015 at 07:00 AM EST
WASHINGTON, Nov 24 (Reuters) - Since last month, U.S. warplanes have struck Islamic State's oil infrastructure in Syria in a stepped-up campaign of economic warfare that the United States estimates has cut the group's black-market earnings from oil by about a third.