The average U.S. retail price of diesel fuel has increased to $1.619 from the previous average of $1.595, the Department of Energy reported recently.

The highest prices were in California, at $1.939; New England, at $1.767; the Central Atlantic region, at $1.736; and on the West Coast, where the average price is $1.851.

The dollar-fifty to dollar-sixty range greeted the Lower Atlantic region, where the average price is $1.571; the Midwest, at $1.579; the Gulf Coast, at $1.536; the East Coast, at $1.629; and the Rocky Mountain region, where the price is $1.599.

Meanwhile, world oil prices have risen to a one-year high due to continuing concerns about the lack of stocks in the United States and instability in oil producer Venezuela, according to BBC News.

The rise has been fueled by a report last week that the United States was not storing enough oil ahead of the summer. It also comes after Venezuela said it might stop supplies to America.

Venezuelan president Hugo Chavez has accused the United States of supporting his protesting political opposition.

The combination of factors are forcing prices up, despite reassurances from Saudi Arabia, the world's largest oil exporter, that it would ensure adequate oil supplies, BBC reported.

Saudi Arabia did not comment on whether it wanted OPEC to call off plans to cut output next month if prices remain high, itself another upward pressure.

Concerns that the United States is not stockpiling enough oil comes from official figures from the Energy Information Administration. Last week, it warned that American oil stocks were at an almost historic low, and stores of gasoline and other oil-based products have also declined.

The EIA findings reportedly shocked the markets because at this time of year, the United States normally builds up its stocks ahead of the high-use period in the summer.