HOLLYWOOD, Md. -- Facing growing concern over the threat of high heating costs, Al Gore proposed tapping the government's emergency petroleum reserve to force down oil prices before winter arrives.

The Democratic presidential candidate also urged Congress to provide $400 million in additional energy assistance for low income families and tax credits to oil distributors to help build up dwindling heating oil stocks.

"We need aggressive action right now," Vice President Gore said Thursday, speaking at an oil distributorship in Maryland.

He also said foreign producers must live up to promises to increase supplies, declaring, "It's time for OPEC to get serious about the supply and price of oil."

Republican rival George W. Bush's campaign complained that taking oil from the reserve could leave the nation vulnerable to foreign suppliers. Bush said the United States should use its "strong hand in the diplomatic circles" to persuade oil-producing countries to increase production.

Both campaigns are scrambling to deal politically with the higher energy prices that have annoyed motorists all summer and soon will be showing up in home heating bills in the Northeast.

Gore used the backdrop of an oil distributorship in southern Maryland's St. Mary's County -- where most people use oil to heat their homes -- to unveil his energy plan. Several hundred supporters showed up at the Burch Oil Co. to listen to the vice president take another swipe at Big Oil, which he said has "profiteered" at the expense of consumer, taking in huge profits this year.

With four large heating oil storage tanks in the background, Gore urged the president to approve a series of "swaps" in which oil -- about 5 million barrels initially -- would be made available to the market. If these releases produced lower prices and eased tight supplies, the Energy Department should make additional releases "to further stabilize prices," Gore said.

Under Gore's plan, oil from the Strategic Petroleum Reserve -- a government stockpile of nearly 600 million barrels of crude intended to counter supply shortfalls -- would be made available to the market through bids. A company would agree to return the oil to the government at a future date, presumably when the price has declined, lowering its value. No actual money would be exchanged.

Reacting to Gore's proposal, Bush spokeswoman Karen Hughes said, "That reserve is intended for strategic and national security purposes, not for election-year political purposes."

She said dipping into the reserve would allow Iraqi leader Saddam Hussein "to literally put America over a barrel." She added, "If we dip into our reserve now, Saddam Hussein may well drop production ... and create a crisis."

Regarding Bush's statement that this jeopardizes the reserve, Gore spokesman Greg Simon called that "a fig leaf for his refusal to take any action," saying the plan includes guarantees that companies return the oil at a later date. And he said there's no total number of barrels the plan envisions using, but said it will be a relatively small amount compared to the nearly 600 million barrels in the reserve.

Bush said Thursday the United States should prod foreign suppliers to make more oil available. "We need to use our strong hand in the diplomatic circles to make it clear to our friends overseas that we don't want them holding our nation and our consumers hostage," he said on the TV show "Live With Regis."

Bush also said there should be more energy exploration at home, and "we need to help low-income seniors with their heating bills."

As he did last summer when gasoline prices soared, the vice president took another swipe at the oil companies, contending they were "profiteering" at the expense of American consumers saddled with $2-a-gallon gasoline during the summer and faced with an expected price shock in the winter heating season.

The Energy Department predicts heating costs will be a third higher on average this winter than last and could go even higher if there is severe weather.

On Wednesday, Bush, campaigning in Pennsylvania, said the Clinton administration -- including Gore -- should "be held accountable for a failed energy policy" that has thwarted domestic oil production and failed to confront the OPEC oil cartel.

Campaigning in Arkansas, Dick Cheney, Bush's running mate, blamed high gas prices on the Clinton-Gore administration, saying Energy Secretary Bill Richardson admitted being "asleep at the switch" when oil prices surged last winter.

He said an internal Energy Department memo last July showed that the administration's own environmental regulations "were one of the major reasons that gas prices jumped to a record highs in the Midwest" over the summer.

Gore running mate Sen. Joseph Lieberman, campaigning in Florida, said Gore's oil reserve proposal "will challenge OPEC and bring the prices of crude and home heating oil down so that they don't cause pain in the average Americans budget ... and endanger the extraordinary growth that our economy has had."

Many member of Congress have been urging the Clinton administration for months to step in and release oil from the strategic reserve.

It was last used in response to an emergency in 1991 during the Persian Gulf War, although some oil was sold to pay for operating the reserve in 1996 and 1997.

Richardson told a group of lawmakers Wednesday that "all options remain on the table" and that the president would not leave consumers "hostage" to high heating oil costs. The White House said President Clinton was still reviewing his options and had not made a final decision. Gore's staff has been included in the administration's deliberations.

A recent memo from Treasury Secretary Lawrence Summers advised Clinton that attempting to drive down prices by opening the reserve "would be a major and substantial policy mistake," The Wall Street Journal reported Thursday. The document said Summers' objections were shared by Federal Reserve Board Chairman Alan Greenspan.

On Thursday, however, Summers said in a telephone interview that Gore's proposal would be "a prudent use" of the reserve and "could be appropriate in current circumstances."

"We have always recognized that this would be, and indeed has been, a rapidly evolving situation and we all need to monitor it closely," he said.

Gore spokesman Chris Lehane said Summers' Sept. 13 memo had concerned the possibility of a withdrawal of as much as 60 million barrels from the reserve -- much more than Gore is proposing.