US retail gasoline prices this week hit an all-time high of US$3.22 a gallon on average, according to the Energy Information Administration (EIA).

Guy Caruso, chief of the Energy Department's statistics arm, concurred with suggestions that retail gasoline prices have not peaked.

He cited continuing problems in Nigeria, a source of easier-to-refine grades of oil for world markets, as well as that nation's need to import refined products such as gasoline and diesel for its own use.

Nigeria "is putting pressure on the global market for refined products," he said. "I am very hesitant to say we've reached the peak."

Retail gasoline prices have been on the march this year. A series of refinery outages and consistent demand from consumers have been the main reasons behind this.

The average price released by the EIA is up 11.5 cents from last week. It is a fraction of a cent below an inflation-adjusted monthly high reached in March 1981. This week's price is up 32.6 cents from a year ago.

Prices are expected to ease once refinery capacity returns and higher prices draw imports from other parts of the world, the report said.

At a separate energy gathering, Energy Secretary Samuel Bodman said, "We seem to be recovering, and hopefully we'll see mitigation of concern soon."