The complexities of Guatemala's past and present problems weighed heavily today among voters as they went to the polls in the country's first presidential election since 1996 peace agreements ended 36 years of civil conflict.

There were few signs of the heavy military presence that marked previous elections, and throughout the day voting was reported to be peaceful at the 7,600 balloting sites. Voter turnout was heavy in a number of polling stations across this capital, and the National Electoral Tribunal estimated that nearly half of Guatemala's 4.5 million voters would cast ballots in a nation that historically has had a low level of electoral participation.

However, an inexplicable shortage of buses that were to transport some voters to polling locations in parts of Guatemala City prompted the opposition Guatemalan Republican Front (FRG) to file a formal complaint with the tribunal, international monitors said.

According to recent pre-election polls, the FRG's candidate, Alfonso Portillo, a 48-year-old lawyer and economist, was the front-runner with about 45 percent of the vote, despite accusations that the party's founder and general secretary, a 74-year-old former military coup leader, was responsible for genocide when he was president in the early 1980s.

Two months ago, Portillo stunned the nation when he admitted he had fatally shot two men, in what he insists was self-defense, in a brawl in Mexico 17 years ago and then fled because he feared he would be unfairly prosecuted. A judge closed the case in 1995.

But Portillo's popularity has grown since the disclosure. He has made the Mexico incident a centerpiece of his populist law-and-order campaign that has resonated with many Guatemalans who view the government as oligarchic, dishonest and incapable of delivering the prosperity and public safety they had hoped would come with peace.

Trailing Portillo by about 12 percentage points, the polls show, is Oscar Berger, 53, a businessman and former Guatemala City mayor who is the candidate of the ruling National Advancement Party. In an effort to counter Portillo's strident anti-establishment message, the National Advancement Party recently intensified efforts to portray itself as a more broad-based party and has counted on concerns about the past of some of the Republican Front's military members, and especially former president Efrain Rios Montt, to boost its showing in today's contest.

The election is also the first in which Guatemala's former Marxist rebels ran as a political party. But polls indicated that Alvaro Colom, 48, an industrial engineer and candidate for the leftist New Nation Alliance coalition, which includes the former guerrillas, was in distant third place. To avoid a Dec. 26 runoff, one of the candidates in the field of 11 must win an outright majority of the votes.

The balloting comes at a time of disappointment and concern over the failure of President Alvaro Arzu's administration to implement key reforms tied to the ambitious three-year-old peace accords that were aimed at rebuilding Guatemala and addressing the social, political and economic problems that fueled the war.

"The government has no interest in those of us living on the fringes of society. The ruling party is nothing but a party of the rich, but now we can change that," said Luis Lima, 27, who is unemployed and voted for Portillo.

Four years ago, Portillo ran strongly against Arzu, who is constitutionally barred from seeking reelection.

Despite 5.1 percent economic growth last year, an estimated 80 percent of the country's 11 million people live below the poverty line. The situation is exacerbated by annual inflation of about 7 percent and sagging coffee and sugar prices worldwide that have hurt export revenues.

Voters today were also electing members to the newly expanded 113-member Congress, as well as local officials in 330 municipalities and 20 delegates to the Central American Parliament.

Some voters said they opposed the FRG because of its association with Rios Montt, 74, the party leader and onetime coup leader accused of genocide during the conflict, in which an estimated 200,000 people were killed or disappeared.

"Mine is a vote against the FRG," said Jose Asturias, a 23-year-old industrial engineer who voted for the ruling party. "It is this very dark past that bothers me. It seems that some people have chosen to forget or ignore the horrible things that happened."

But Guatemalans are also concerned about widespread crime and a justice system that remains dysfunctional due to corruption, incompetence and inefficiency. These frustrations have drawn many people to Portillo, who openly sympathized with leftist guerrillas during the war but has found common ground on issues with Rios Montt, who ruled as a dictator for 17 months in 1982 and 1983.

"What we saw was that General [Rios] Montt made strong laws. He will help against the violence, and we need change," said voter Tomas Doroteo.

Rios Montt, who is barred from being elected president, is a candidate for a seat in Congress on his party's ticket, and is thought likely to win. That would position him to become the chamber's next president. Despite assurances from Portillo to the contrary, critics have speculated that Rios Montt may try to run the country behind the scenes should Portillo win the presidency.

The ruling party and other opponents of Rios Montt's party have tried to paint it as a vestige of Guatemala's old military guard. "Let's reject the violence, the blood and the terror the opposition party stands for," Berger told thousands of supporters a week ago. "Our fatherland is in peril. Let us not allow our peace and a process that includes all Guatemalans to be taken away from us."

CAPTION: Opposition presidential candidate Alfonso Portillo greets supporters after voting. Preelection polls showed him to be the front-runner.