Oil prices climbed to three-week highs today after a weekend bombing in Saudi Arabia heightened fears over the supply of Middle Eastern crude.
December New York crude futures gained 40 cents to $31.25 a barrel; London's benchmark Brent crude rose 49 cents to $29.40 a barrel.
Suspected al-Qaeda suicide bombers killed at least 17 people in the Saudi capital Riyadh on yesterday, causing fears more such attacks might destabilise the flow of crude from the world's largest producer.
"The psychological impact of these terrorist attacks is that what began in Iraq is now happening in Saudi Arabia, and who knows where it will happen next? In the UAE, Kuwait?" said Mr Katsunori Watanabe, director of research at Japan's Nihon Unicom Corp. The Middle East supplies a third of the world's crude oil.
Signs of a brighter US economy and stronger fuel demand have also supported the market over the past week, as a fall in oil product stocks renew worries over winter heating oil supplies.
The US Labor Department on Friday said the number of workers soared by 126,000 last month. In October, the government reported that the economy grew at more than 7 per cent in the third quarter, its fastest rate since the mid-1980s.