New York's main contract, light sweet crude for February delivery, rose $US1.69 to $US39.40 a barrel, on top of a gain of $US2.36 to $US37.71 in US trades on Friday.
Brent North Sea crude for February delivery rose $US1.64 to $US40.01, after rising $US1.76 to $US38.37 in London on Friday.
Analysts said the surge in prices was partly due to evidence that OPEC was cutting output as announced two weeks ago.
The Organisation of the Petroleum Exporting Countries (OPEC) is starting to notify customers about the extent of production cuts, said Dave Ernsberger, Asia senior editorial director of Platts, an energy information company.
"People are starting to see evidence on OPEC cuts,'' he said.
Ernsberger said the United Arab Emirates gave notice at the weekend of output cuts between 3 to 15 per cent, an example that cartel nations are serious about reducing production.
OPEC's previous output cuts have often been met with only partial compliance. Ernsberger said that with many traders still on holiday, market liquidity is low and price movements can be exaggerated.
Prices for the New York contract slid for nine sessions before bucking the trend last Friday, while Brent posted its lowest price in more than four years last Wednesday.
Two weeks ago, OPEC agreed to cut output by 2.2 million barrels per day but prices continued to fall.
Analysts have said recent US data showing that the world's biggest economy - and largest energy consumer - remains mired in a recession are likely to keep crude prices under pressure in the short term.
A sharp global downturn has slashed the world's demand for energy, pulling prices sharply lower since record highs above $US147 per barrel in July.
New York crude plunged earlier this month to below $US33, its lowest point for almost five years as weak economic data around the world stoked concerns about the effects of a sharp global slowdown.
With recession curbing the world's appetite for energy, analysts say, prices risk slumping further in 2009.
