Former army General Prabowo Subianto, who lost Indonesia's presidential election, said he would challenge the result at the country's Constitutional Court.
The move was announced by his spokesman on Wednesday, a day after the election commission named his rival, ex-Jakarta Governor Joko Widodo, the winner of the July 9 vote.
Subianto said Widodo's campaign took part in large-scale vote-buying and other fraud and accused the election commission of not doing its duty in investigating the claims.
The court challenge could about a month to complete. Most analysts think it will prove unsuccessful.
Edward Aspinall, an expert in Indonesian politics at the Australian National University, told VOA it would be difficult for the court to overturn a six-point difference in the final results.
"I think the chances are pretty much close to zero. And there would be no precedent in recent Indonesian electoral history of a Constitutional Court overturning a result to that extent,” Aspinall said. He also suggested the fraud allegations, “from what we can see, don't seem to be particularly strong."
There have been no reports of violence, though thousands of police and military forces have been deployed in the case of unrest.
Aspinall said many groups affiliated with Subianto have shown a willingness to use violence in the past, but he doubted whether that will be the case this time.
"My sense is that the further we go with the process, the chances of that sort of thing begin to diminish, partly because the coalition that coalesced around Prabowo during the election campaign is really starting to disintegrate," Aspinall said.
President-elect urges cohesion
Speaking Tuesday after the official results were released, Widodo, the president-elect with 53 percent of the vote, said it was time for the country to come together after a hard-fought campaign.
“I am certain that the struggle to achieve Indonesia that is sovereign, independent and true to our character can only be achieved if we work together. And now it is the time to work together," Widodo said.
World leaders have already begun applauding Widodo on his victory.
U.S. Secretary of State John Kerry issued a statement congratulating Widodo and saying Washington looks forward to working with the new Indonesian president.
The 53-year-old Widodo, also known by his nickname Jokowi, is seen by many as a reformer and a rare candidate without links to Indonesia's longtime dictator, Suharto, who was ousted in 1998 after 31 years. He died a decade later.
Subianto, a former son-in-law of Suharto, campaigned on a strong nationalist platform.
Many were concerned he would steer the country in an authoritarian direction. During his time as an army general, he was accused of rights abuses, including overseeing the arrest of democracy activists.
Shaun Levine, a senior analyst for South East Asia at the Eurasia Group, said Widodo's outsider status would help increase the field of candidates in future elections.
"For Joko Widodo to win the election by the margin that he did, in the sense that going forward that you will have more of an opportunity for political outsiders to join in the elections and become a member of parliament president, is very positive for Indonesia," Levine said.
Indonesia is the world's most populous Muslim country, with 250 million residents, and has Southeast Asia's biggest economy.
VOA's Bill Gallo contributed to this report, which was produced in collaboration with the VOA Indonesian service.