The price of gasoline, after declining for months, has risen 7 to 13 cents a gallon at some Washington area service stations in recent days, the American Automobile Association said yesterday.

The finding was based on early results of the AAA's annual Easter gas price survey, according to Mary Anne Reynolds, AAA Potomac division representative. She said final survey results, comparing current prices at 100 stations with their Christmas prices, will be released next week.

"But we know from preliminary calls to 30 stations that the sharpest increase has come since early February, when gasoline was selling for 98, 97 and even 91 cents a gallon," she said. "Now it is well over $1 a gallon at those same places."

One Exxon dealer in Falls Church was selling regular gasoline for 91 cents a gallon last month to self-service cash customers, but the dealer now charges $1.04 a gallon for that gas, Reynolds said. She said an Amoco dealer in the District had raised his self-service cash price for regular gas from 98 cents a gallon to $1.05.

Those prices, despite the sharp increases, still appear to be among the lowest in the area, the survey indicated. For example, the AAA found regular gas selling for as much as $1.10 a gallon at some stations, unleaded regular for as much as $1.27 a gallon and premium unleaded for as much as $1.39 a gallon.

The preliminary survey found that gas prices are now about the same as they were in the Christmas survey. Prices dropped after Christmas, enabling Washington area motorists to "enjoy some good, cheap driving in February," Reynolds said. But the February bonanza appears to have ended now that prices are returning to a higher level.

Reynolds said that gasoline prices traditionally fall during the winter and rise in the spring, as motorists take to the road, boosting demand for fuel. "Those increases generally don't come until late May, when we are approaching Memorial Day weekend," she said. "But they seem to be early this year -- two months early."

Dealers said this spurt in gas pump prices reflects increased wholesale costs. "Every half hour, it seems like we get another call that there's been an increase," said Dick Cooper, executive director of the Virginia Service Station Dealers Association.

Three of the largest local gasoline suppliers -- Amoco, Shell and Exxon -- have raised their prices between 4 and 4.4 cents a gallon since early February. Company spokesmen said the increases were made in response to market conditions.

"It sounds simplistic," said Roger Friskey, an Amoco representative. "But the price really is determined by supply and demand. When the market tightens, prices go up. When the market weakens, prices go down."

That goes for station dealers as well as oil company managers, he said. "A dealer may raise his pump prices, but if his volume drops, then he'll drop his price," Friskey said.

One oil company official described retail gasoline pricing this way: "It's whatever the market will bear, but sometimes it won't bear very much."

The official suggested that wholesale and retail gasoline prices fell to an unnaturally low level after Christmas because of mild December weather that prevailed through much of the country, and that this led to lower heating oil demand and a more abundant supply of crude oil. When cold weather hit in January, demand for heating oil soared and crude oil prices began climbing back to a more normal level, the official said.

"There also may be some pressure on the 'spot' market due to the hostilities in the [Persian] Gulf," he said.

But Roy Littlefield, director of the Greater Washington-Maryland Service Station Association, said he was surprised by the wholesale gasoline price increases. "We are told consistently that there is a surplus," he said, yet wholesale prices have been going up.

"This goes against conventional wisdom," Littlefield said.