Oil was little changed at around $133 a barrel this morning after news of another attack on Nigerian oil facilities refocused concerns on immediate supplies.
US crude stood at $133.05 a barrel this morning little changed from late electronic trade yesterday, when the New York Mercantile Exchange trading floor was shut for the Memorial Day holiday. Prices were up 86 cents versus Friday's close.
London Brent crude rose 43 cents to $132.80.
Oil prices have risen nearly 40 per cent this year, supported by the extended slide in the US dollar as well as growing fears about the industry's ability to keep pace with demand over the next decade due to disappointing non-OPEC output growth.
Yesterday, OPEC President Chakib Khelil reiterated that the cartel would not be meeting earlier than its scheduled gathering in September to discuss rising prices, the website of the Libyan National Oil Corporation (NOC) reported.
OPEC has been adamant that the market remains well balanced and there is no need to raise production levels, blaming the rise in prices on financial speculators or other factors outside its control.
Prices rose on Monday as Royal Dutch Shell said it was forced to cut production in Nigeria after rebels from the southern Niger Delta blew up an oil pipeline.