Indonesians vote Monday in their first direct presidential election, with polls showing incumbent Megawati Sukarnoputri in danger of failing to make an expected runoff between the top two finishers in a field of five candidates.

Opinion surveys released last week gave a former chief security minister, Gen. Susilo Bambang Yudhoyono, a lead of more than 20 percent over his nearest rivals but slightly less than the 50 percent-plus threshold needed for an outright victory.

Indonesia, the third-largest democracy in the world, is selecting a president and vice president at a time when many people have grown disillusioned with Megawati's lackluster performance in fighting corruption and reviving a listless economy.

If Megawati is ousted, it would mark a stunning reversal for a woman who is not only the daughter of Indonesia's first president but also symbolized the country's democratic aspirations after longtime dictator Suharto was forced from office by protesters in 1998. Megawati, a former vice president, gained the top spot three years ago.

But her defeat would also represent a significant step for democracy in Southeast Asia, where in the last generation only Thailand has removed a leader through the electoral process.

A poll released Friday by the Indonesian Survey Institute showed Megawati running second, slightly ahead of another general, Wiranto, who had been armed forces commander under Suharto. A survey released the day before by the International Foundation for Electoral Systems showed her in third place.

Both polling organizations, which performed well in predicting the outcome of Indonesia's parliamentary elections in April, gave Yudhoyono about 43 percent of the vote. A runoff between the top two finishers would be held Sept. 20.

Yudhoyono's strong showing in these polls, coupled with Wiranto's mounting popularity, has raised concerns among some Indonesians that the country's military may be positioning itself to retake control. The two retired generals have responded that they are committed to the democratic reforms enacted after Suharto's downfall.

In recent weeks, Megawati has sought to resuscitate her ailing campaign, wading into crowded street markets and bus terminals after having spent much of her term sequestered in the presidential palace. But during a televised debate Wednesday, she stumbled, seeming uncomfortable and ill-informed.

Formal campaigning ended Friday. The three top contenders visited the graves of their ancestors Saturday, with Megawati paying respects to her father, Sukarno. On Sunday, several presidential and vice presidential candidates, not including Megawati, appeared on an election eve television program singing and reading poetry.

As the campaign wound down, workers across Indonesia began setting up 575,000 polling stations, many consisting of little more than a tarp strung between bamboo polls. About 153 million Indonesians are eligible to vote, and election observers said they expected that more than 90 percent would participate in choosing the president, a task previously carried out by the parliament.

In the provincial capital Semarang, on the island of Java, Agung Priyono, a security guard, said he had been a "true believer" in Megawati during the 1999 parliamentary election campaign, dressing in red, the color of her party, and joining thousands of others on his motorcycle to rally support. "I was hoping Mega could bring about changes in Indonesia," said Priyono, 25.

But he said he now supported Yudhoyono, who resigned from Megawati's cabinet in March. "Megawati is a weak leader and doesn't stand up for the little people. She has ignored our trust," he said.

In central Jakarta, Sunaryono, a retired navy officer, said his entire neighborhood had once backed Megawati. Now, Sunaryono, 63, said he was practically her lone supporter, out of loyalty to her father, Sukarno.

"Megawati doesn't really communicate with the people about her achievements. And because she holds power in her hands, she gets blamed for all sorts of things whether they're her responsibility or not," he said, adding that Yudhoyono is the local favorite.

Special correspondents Noor Huda Ismail in Semarang and Natasha Tampubolon contributed to this report.

Women pray at a mosque in Jakarta on the eve of Indonesia's first direct presidential election. According to polls, Gen. Susilo Bambang Yudhoyono and Gen. Wiranto are the front-runners, ahead of President Megawati Sukarnoputri. Indonesian election officials prepare for Monday's presidential election by delivering ballot boxes in the Baliem Valley, in a remote part of Papua province.