New York oil prices gained more than $US2 ($A1.96) following an unexpected drop in US inventories and speculation the European Central Bank (ECB) will soon cut interest rates. Benchmark West Texas Intermediate for June delivery gained $US2.25 ($A2.20) on the New York Mercantile Exchange to settle at $US91.43 ($A89.47) a barrel, the highest level since April 11. In London, Brent crude for June delivery rose $US1.42 ($A1.39) to $US101.73 ($A99.54) a barrel. The US market reacted strongly to "the big drop in gasoline inventory which was a bit of a surprise," said Michael Lynch of Strategic Energy and Economic Research. Stocks of petrol fell 3.9 million barrels, almost 10 times more than expected by analysts surveyed by Dow Jones Newswires. Gold futures have climbed, taking cues from signs of strong physical buying of the metal as some investors saw its recent slump as a buying opportunity. The most actively traded contract, for June delivery, rose $US14.90 ($A14.58), or 1.1 per cent, to settle at $US1,423.70 a troy ounce on the Comex division of the New York Mercantile Exchange. Dealers of gold coins and bars in trading hubs world-wide have reported a sharp increase in activity following gold's historic sell-off last week. Some buyers, gold dealers and traders said, viewed gold's two-session, $US200-an-ounce retreat as an appealing opportunity to buy the metal at prices not seen in more than two years. Copper has surged above $US7,000 ($A6,849) a tonne after investors went bargain-hunting following hefty falls, but further gains have been capped by uncertainty about the outlook for global economic growth. Three-month copper CMCU3 on the London Metal Exchange (LME) closed 2.3 per cent higher at $US7,029.50 a tonne, after earlier hitting a session peak of $US7,053, its highest since late last week. It had reached an 18-month low of $US6,762.25 a tonne on Tuesday. The metal, used in power and construction, fell 5.6 per cent last week and has shed 16 per cent since touching $US8,346 in February, its highest in 2013.