At 11:00 am (0300 GMT) New York's main contract, light sweet crude for delivery in February, was down 17 cents to 58.15 dollars a barrel from 58.32 dollars in late US trades Wednesday.

The contract had tumbled 2.73 dollars in US hours to its lowest point since mid-November.

Brent North Sea crude for February fell five cents to 57.91 dollars a barrel, after dropping 2.48 dollars earlier to a November 17 low.

Victor Shum, senior principal at Purvin and Gertz Inc in Singapore, said the unusually warm winter weather in the Northern hemisphere is still the major factor driving the drop in oil prices.

"Weather remains the main catalyst," said Bart Melek of BMO Capital Markets in New York.

"We've had very unseasonal weather in December and the first week of January," Melek said during US trading hours.

US demand for heating oil in the week to January 6 is expected to be about 33 percent below normal because of the mild conditions in the country's northeast, analysts said.

The strong US dollar and stock markets on Wednesday may also have contributed to the sharp decline in oil prices, Shum said.