US oil prices have jumped to a four-month high due to the effects of a cold winter in the US and rising concerns about stability in some key oil exporters.
US benchmark West Texas Intermediate for March delivery on Tuesday rose $US2.13 to $US102.43 a barrel on the New York Mercantile Exchange, the highest closing price since October 10.
European benchmark Brent oil for April delivery gained $US1.28 to close at $US110.46 on London's Intercontinental Exchange.
Cold weather in much of the United States has lent upward support to oil prices, as inventories of home heating oil continue to dwindle. US oil prices last week closed for the first time in 2014 above $US100 a barrel.
"Between the winter that's going to hang on for a bit longer and tight inventories of heating oil and a strong economy and some good upside momentum... we're in an uptrend that doesn't show any sign of breaking," said Addison Armstrong, director of market research at Tradition Energy.
While milder weather is forecast this week in some US cities, meteorologists expect another wintry blast after that.
Matt Smith, analyst at Schneider Electric, said "pockets of geopolitical tension" are also a factor in the latest surge in oil prices.
Smith pointed to "subdued" output in Libya, where political unrest and a blockade of oil export terminals has depressed production for months.
Analysts also cited Nigeria, South Sudan and Venezuela as countries where output has either already been curtailed or faces uncertainty due to political conflict.
