Global oil prices powered higher, pushed in part by a spike in gasoline prices and renewed market optimism about US demand. New York's main contract, West Texas Intermediate (WTI) for August, leaped $US1.04 from Thursday to finish at $US105.95 a barrel. The European benchmark, Brent North Sea crude for delivery in August, climbed $US1.08 to settle at $US108.81 in London trade. Gold prices edged lower as a stronger US dollar and disappointment over gold purchases by top consumer India offset support from weaker US data. Copper closed lower on the London Metal Exchange (LME), weighed by a strong US dollar and concern over demand for the commodity from top metals consumer China.