Global oil prices soared Thursday to new four-month highs, as the US Federal Reserve announced a new round of quantitative easing to stimulate the flagging economy. The market also surged higher as traders eyed simmering geopolitical tensions in the crude-rich Middle East. New York\'s main contract, West Texas Intermediate (WTI) or light sweet crude for October delivery, leaped to $1.30 to $98.31 a barrel. In London, Brent North Sea crude for October jumped 94 cents to $116.90, its best level since May 2. The Fed pledged to keep its benchmark interest rate ultra-low through the middle of 2015 and launched a $40 billion a month program to buy in mortgage-backed bonds, aiming to drive down long-term rates and boost investment, spending and hiring. Analysts were dubious that would help the economy much, given other challenges to growth, but the markets liked it. \"After some initial waffling and that saw prices back to unchanged the market determined that it was good enough and risky assets including crude oil enjoyed a solid day. Ongoing and rising Middle East tensions certainly add to the buying interest,\" said Laney Sweatt at BMO Capital Markets. Meanwhile, India sparked turbulence in the local market when the government ordered a 12 percent hike to diesel prices, reversing a cut three months earlier.