Oil prices climbed, finding support from political turmoil in Ukraine and some oil-producing countries and the return of cold weather in large parts of the United States.
New York's main contract, West Texas Intermediate (WTI) for delivery in April, closed at $US102.82 a barrel on Monday, a gain of 62 cents from Friday.
In London trade, Brent North Sea crude for April added 79 cents, settling at $US110.64 a barrel.
The WTI contract was benefiting from expectations of stronger demand for heating oil as another winter cold front was expected to grip much of the United States this week, analysts said.
Bob Yawger of Mizuho Securities USA highlighted that crude oil supplies at the Cushing, Oklahoma terminal, which serve as a price reference for WTI, totaled 35.9 million barrels last week according to official data, roughly 14.8 million barrels below the year-ago level.
Traders are expecting the Department of Energy to report another drawdown at Cushing on Wednesday.
Crude-oil prices also were being supported by geopolitical factors "heating up around the globe," said Phil Flynn of Price Futures Group, who cited Libya, Venezuela and South Sudan, "with the most dramatic events taking place in the Ukraine."
Ukraine issued an arrest warrant Monday for its ousted pro-Russian president over "mass murder" and appealed for $US35 billion in Western aid as Moscow denounced Kiev's new reformist team as illegitimate.
"The threat and uncertainty surrounding Ukraine has Europe slowing exports of oil and products as they fear they may need them if they have to use them to offset the loss of Russian gas," Flynn said.
John Kilduff of Again Capital said that "anytime there is political turmoil, oil is becoming a safe place to bet on".
There are some energy implications in Ukraine's situation, he said, "but we'd really have to see some significant move from Russia to have a real effect, to move the needle one way or the other".
