MEXICO CITY (AP) _ American observers who scrutinized Mexico's presidential contest say the vote was cleaner than in past elections, but they and others still found widespread irregularities.

Civic Alliance, the largest Mexican election monitoring group, said it found that voters were pressured in about a quarter of rural precincts.

''The quality of elections is in doubt,'' said Rogelio Gomez, a board member of the Alliance, which groups some 400 organizations.

Alliance officials said the problems, which included large numbers of eligible voters removed from voting lists, might not have been enough to swing the election.

But, said Alliance official Enrique Calderon, ''Whether you steal 100 pesos or a million from a bank, it's still called a bank robbery.''

Observers were allowed for the first time to monitor the election, under sweeping reforms designed to clean up a fraud-ridden system that has kept the Institutional Revolutionary Party, or PRI, in power for 65 years.

PRI candidate Ernesto Zedillo won the vote, having built an insurmountable lead by late Tuesday. Final results were not expected before today.

The government spent $730 million to overhaul voter rolls, issue photo identity cards, create a new indelible ink to prevent double-voting and create an office for a new election fraud prosecutor.

About 900 foreign ''guest'' observers and 82,000 domestic poll watchers took part in what was the most-scrutinized election in Mexican history.

''We have seen a more open election,'' said former Democratic Party Chairman Paul Kirk, president of the National Democratic Institute. ''What happened on Sunday was something that has never happened in Mexico before.''

Government authorities said Tuesday as many as 77 percent of Mexico's 45.7 eligible voters cast ballots Sunday in an unprecedented exercise in democracy.

''Whatever skepticism may have been in people's minds ... the turnout here in Mexico was a powerful statement made by the most important group who participated in the elections,'' Kirk told a news conference Tuesday.

Kirk released a preliminary report of the International Republican Institute and National Democratic Institute, which sent a joint delegation.

In twenty-five states observed, the 34 delegation teams found only ''minor irregularities and isolated instances of intimidation of voters.''

The report added that the observers found ''no evidence to suggest that they would have affected the outcome of the presidential contest.''

But some foreign observers glossed over serious problems, said Enrique Oteiza, an Argentine researcher from the University of Buenos Aires.

They are ''accepting things that they would never accept in their own countries, in the United States or in Europe,'' said Oteiza, who reported witnessing numerous irregularities in Mexico state.

Most of the foreigners' complaints centered on ruling party representatives, who were not election officials, accused of entering polling booths to ''help'' people vote.

They also complained of government employees frightening people into voting for the PRI by threatening to cut off government aid, such as food coupons or farm assistance.

Some foreign observers harshly condemned the election.

''I just saw gross fraud,'' said Katie Villaire, a sociology professor from Grand Rapids, MI, in Mexico with the San Fransisco-based Global Exchange, which sent observers to remote areas of Mexico.

Eighty members of Global Exchange held a protest today in front of the offices of media giant Televisa, saying it broadcast only the group's brief remarks about progress in the election and ignored comments about problems.