Oil prices have spiralled to a nine-month high of over $69 a barrel, fuelling worries of another bout of unstable oil prices, as Nigerian oil unions called a strike for this week. Nigerian oil unions have called a general nationwide strike from tomorrow to protest government price increase on automobile fuel.

Also pushing up energy prices were attacks on two Nigerian oil facilities, which cut oil output, by angry villagers and gunmen.

In March, Nigeria was the third-biggest exporter of oil to the US behind Canada and Mexico, accounting for an average of nearly 1.4 million barrels a day, according to the US energy department data.

Analysts said the news out of Nigeria was prompting large funds to buy energy futures, driving prices higher. But analysts are skeptical that the unions will follow through and actually strike.

Brent crude for August delivery added 71 cents to settle at $72.18 a barrel in London.

Heating oil futures rose 2.36 cents to settle at $2.0342 a gallon, while natural gas prices fell 22.8 cents to settle at $7.69 per million British thermal units.

Light, sweet crude for July delivery rose $1.09 to settle at $69.09 a barrel on the New York Mercantile Exchange, while gasoline futures for July rose 0.42 cents to settle at $2.2643 a gallon, even as pump prices fell 0.3 cents overnight to a US national average of $3.005 a gallon, belying predictions by analysts last Friday that they would not decline further.

From its peak in late May, retail gasoline has fallen 22.2 cents.