The Pentagon has started bombing Islamic State (IS) oil trucks because it says airstrikes on militant-controlled oil facilities have been only "minimally effective."
U.S.-led coalition spokesman Colonel Steve Warren on Wednesday said airstrikes destroyed 116 oil tankers in eastern Syria since Sunday.
He said U.S. planes dropped leaflets warning the drivers to jump out of the trucks and run away. Warren said it is unlikely the drivers belong to IS.
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"They're probably just civilians so we had to figure out a way around that. We're not in this business to kill civilians. We're in this business to stop the Islamic State group," he said.
Warren said the airstrikes on IS oil facilities were not too successful because he said the militants quickly repaired the damage.
IS uses millions of dollars in illicit oil revenue to help fund its operations.
Warren also criticized Russian airstrikes in Syria as generally being unfocused and scattershot, saying it would be "no surprise" if they killed civilians.
"Those are the type of tactics needed only if you don't possess the technology, the skills and the capabilities to conduct the type of precision strikes that our coalition conducts," he said.