JAKARTA: Indonesian presidential hopeful Joko Widodo urged his supporters Thursday to carefully monitor vote-counting in a bitterly fought election amid concerns about cheating, a day after both he and his rival declared victory.

The brother of his opponent, ex-General Prabowo Subianto, meanwhile lashed out at Widodo for attempting to “hijack” the democratic process by coming out with an early claim of victory Wednesday.

The fight between Widodo – the first serious presidential contender without roots in the era of dictator Suharto – and Prabowo is the most closely fought race for the presidency since the end of authoritarian rule in 1998.

Both candidates claimed to have won the poll in the world’s third-biggest democracy based on unofficial tallies, but Jakarta governor Widodo had the backing of more – and more credible – polling agencies.

Prabowo, a top military figure in the Suharto era, has said that other polls showed him winning, and the unofficial tallies are not conclusive.

Official results are not released until July 22, due to the complexity of holding elections across the world’s biggest archipelago nation, and officials are undertaking the mammoth task of counting tens of millions of votes by hand.

Widodo, known by his nickname Jokowi, expressed concerns about vote fraud in a country where corruption is rife and bribery, especially in the public sector, is common.

The presidential election campaign has already been the dirtiest and most polarizing in the young democracy, marked by a flood of smears, which Widodo blamed for a rapid loss of his support ahead of polling day.

Speaking to journalists in the capital Jakarta, Widodo called on volunteers and party members to “monitor and guard the process at polling stations. I call on all parties not to interfere with the sincere aspirations of the Indonesian people.”

However Prabowo’s brother, Hashim Djojohadikusumo, an enormously wealthy businessman who helped bankroll the ex-general’s campaign, hit back, claiming Widodo had made a “foolhardy and irresponsible” early declaration of victory.

“The democratic process is in serious danger of being hijacked by the other side,” he said, without going into details.

Prabowo made his own declaration of victory around an hour after Widodo made his.

Investors already believe that Widodo, seen as a potential reformer and a clean leader in the graft-ridden country, is on course to win.

The Jakarta stock market surged 2.5 percent at the open Thursday and the rupiah rallied. The market sunk slightly in afternoon trade and closed up 1.46 percent.

The closely fought race has sparked concerns there could be unrest, and President Susilo Bambang Yudhoyono late Wednesday met both candidates at his residence outside Jakarta and urged them to restrain their supporters.

“We call on all party members and volunteers not to organize a parade. It’s better just to give thankful prayers,” Widodo said after meeting the president.

There were no reports of large rallies Thursday.

Several polling agencies, which have accurately predicted the result of previous elections in Indonesia, gave Widodo a lead of several percentage points.

Prabowo, 62, however, insisted that – lesser-known – survey agencies followed by his camp gave him a narrow lead.

Should he be declared the official winner, 53-year-old Widodo is expected to usher in a new leadership style and consolidate democracy.

He shot to prominence in 2012, when he was elected as the governor of Jakarta, and won legions of fans with his common touch. He would make regular tours of the metropolis’ sprawling slums dressed in casual clothes.

Prabowo, in contrast, was head of the feared special forces under Suharto, admitted ordering the abduction of democracy activists before the dictator’s downfall in 1998 and was formerly married to one of his daughters.

He has won support by playing up his military background, in a country where many yearn for a strong leader, but critics fear he may roll back democratic gains made since the fall of Suharto.

Some 190 million voters were eligible to cast ballots in Indonesia’s third direct presidential election since the end of authoritarian rule.

Polling went smoothly across the country, from eastern Papua to the main island of Java and jungle-clad Sumatra in the west, and no major disruptions were reported.