Opposition presidential candidate Jackson Doe presented a long list of alleged irregularities in last week's election to U.S. Ambassador Edward Perkins today and told him opposition politicians fear retribution from the country's current military leader, Samuel Doe, it was learned here.

While the government of Samuel Doe (no relation to Jackson Doe) claimed to be scrupulously counting votes cast in the election, a large mound of ballots was found burning yesterday about 40 miles north of this capital city.

The charred ballots, which were photographed by local reporters and dispatched by opposition parties to the U.S. Embassy here, are the most dramatic evidence of what appears to be a wide-ranging effort by Samuel Doe's supporters to alter the results of the election.

Based on reports from major polling centers across Liberia, authoritative independent observers have confirmed claims by the opposition Liberian Action Party that its candidate, Jackson Doe, won last week's election. No official results have been released yet by the government.

The U.S. government, which bankrolls nearly a third of the Liberian budget, has been directed by Congress to cut off $86 million in aid to Liberia if the election is found not to be "free and fair."

In the election, which Samuel Doe hailed last week as "the first test of the truly democratic experience" in Liberian history, the one-time master sergeant turned commander in chief of this West African nation was pitted against three civilian candidates.

On the eve of last week's election, President Doe appeared on state-owned television to deliver a speech on his regime's march toward democracy.

"Our commitment has been unique in the history of military governments anywhere," he said. "This is our first test of the truly democratic experience . . . . History will be our judge."

Irregularities began one week ago when record numbers of Liberians turned out for an election that, in theory, afforded them a greater voice in choosing a leader than ever before in the 138-year history of this nation that was founded by freed American slaves.

On election day, opposition observers were prevented from monitoring voting at military barracks, where some voters were free to vote as many times as they wished.

Questioned two days later about this, Emmett Harmon, chairman of Liberia's Special Election Commission, said he saw no reason to question the voting. Harmon, a 72-year-old lawyer, was appointed by Samuel Doe, as were all the members of the election commission.

Harmon rejected the validity of all election-night vote counts that were monitored by observers from opposition parties. Laws that Doe personally approved for this election give opposition parties the right to observe vote-counting.

Last weekend, in a move that also appeared to violate election laws, Harmon "handpicked" a 50-member committee to conduct -- in private -- an official ballot count.

According to independent observers here, members of the counting committee include two senior aides to Doe, 19 members of Doe's Krahn tribe (a minority grouping here than makes up 5 percent of Liberia's 2 million population) and many avowed supporters of Doe's political party, the National Democratic Party of Liberia.

The opposition Liberian Action Party yesterday charged, and independent observers confirmed today, that ballots cast against Doe were pulled from ballot boxes last weekend and replaced with ballots for him.

The Action Party claimed that all ballots from Nimba County, the nation's second-largest county, were taken from election headquarters in Monrovia and burned in the smoldering pile found north of here yesterday.

A senior member of Doe's government said last weekend that 95 percent of Nimba County voted against the head of state.

Documents here show that the Liberian government ordered 1 million presidential ballots from a printer in Britain, 250,000 more than the number of registered voters in the country.

The observer said Doe's party has decided to announce that the head of state officially won 45 percent of the vote, while Action Party candidate Jackson Doe won 40 percent and other two candidates split the remainder of the vote.

Samuel Doe came to power in 1980 when he led a group of noncommissioned officers who entered the presidential mansion here and assassinated the president, William R. Tolbert, Jr. Since then, the U.S. government has increased assistance sixfold to Liberia.

The avowed purpose of American largess here was to pressure Doe to hold elections that would return the country to civilian rule.

Leading opposition politicians today argued that the U.S. government should pressure Doe's government to call new elections or resign.

"Once the results are announced, there is very little we can do. The next step should be the intervention of friendly western governments, particularly the United States," said one top opposition politician here, insisting on anonymity for fear of retribution.

During the past week, reports of election irregularities have been published daily in local newspapers and on state-owned television here.