Almost 10 percent of the service stations in the Washington area have increased the price of gasoline in recent weeks, spurred by higher wholesale costs, according to a survey by the American Automobile Association.

Half of the 100 dealers surveyed said their tank wagon prices, the wholesale charge they pay for gasoline, climbed by as much as 16 cents a gallon in April. Some dealers said they had raised gasoline prices from 1 to 5 cents a gallon and predicted even higher prices this summer. Although the average price for all grades of gasoline in the Washington area has dropped 15 cents since mid-March, AAA spokeswoman Mary Anne Reynolds said the differences in wholesale gasoline prices will have an impact on local prices, which are typically higher during the summer.

The average price for leaded, premium and unleaded gasoline at full-service and self-service pumps, has dropped from $1.22 a gallon to $1.07, according to the AAA survey.

Many dealers reported, however, that they are not trying to pass on all of the wholesale price increases to customers in an effort to lure summer motorists. Reynolds said that may help keep some prices down, but said those efforts will be countered by the dealers who receive their fuel from independent suppliers that have imposed the sharpest wholesale price increases. Price increases among those stations may spark higher prices among other dealers, according to Reynolds.

"Many [dealers] seem eager to keep the prices down to keep the competition," Reynolds said.