World oil prices extended losses today on expectations of milder weather in the United States, the world's biggest consumer of energy, analysts said. New York's main contract, light sweet crude for delivery in February, dropped 35 cents to 57.81 usd per barrel in electronic trading. In London, the price of Brent North Sea crude for February delivery fell 28 cents to 56.01 usd per barrel. "Crude futures remained under pressure from the mild US weather lowering demand for heating oil," analysts at the Sucden brokerage firm said. Prices were weighed down also by crude output returning to normal in Nigeria after a pipeline attack there last week, they added. Temperatures in the US northeast region, the world's largest consumer of heating fuel, were expected to rise further above normal levels by the end of the week, according to weather forecaster Meteorlogix.