Brent crude moved above $71 a barrel for the first time in three years on Thursday, pushed higher by the weakening dollar despite inventory data that showed US stockpiles increased last week.
The global crude oil benchmark climbed as high as $71.06 a barrel in early trade and by the time European markets were opening it stood 0.55% higher at $70.92.
Nymex West Texas Intermediate, the US benchmark crude price, rose 0.9% to $66.20.
Dollar-denominated commodities were mostly higher on the commodity futures exchanges as the US currency continued to slide.
The dollar index, a measure of the greenback's relative strength against a basket of its six main rivals, fell a further 0.12% to 89.09 on Thursday. The measure is down 3.3% since the start of the year.
A weaker US currency presents an attractive buy signal for commodity investors as it makes purchases of dollar-denominated assets less expensive in rival currencies.