U.S. Treasury Secretary Janet Yellen said on Wednesday that sanctions imposing a full ban on Russian oil exports would likely result in “skyrocketing” global prices that would hurt the United States and its democratic allies. Yellen told the U.S. House Financial Services Committee she hopes oil companies in the United States and elsewhere can ramp up production in the next six moths, enticed by higher prices, which may allow for tougher restrictions on Russian oil.