Jakarta, Indonesia(CNN) Police and protesters angry at Indonesia's election result have battled for a second night on the streets of Jakarta, after six people were killed and more than 200 injured in the initial clashes.

Hundreds rallied on both Tuesday and Wednesday night, throwing stones and firecrackers at police as smoke billowed from cars that had been set alight.

Protesters chanted "Down with Jokowi" and "Prabowo our President!" on Wednesday night, as police in riot gear responded with teargas and water jets.

Indonesian riot policemen fire teargas at demonstrators on May 22, 2019 in Jakarta, Indonesia.

President Joko Widodo, who won a second term after being proclaimed winner on Tuesday of the April election, said the situation was under control.

"We will not give rioters space to destroy our country. We do not have a choice, the military and police will take firm action in line with the law. To all whom I respect, the situation is under control," the president, known as Jokowi, said Wednesday.

His defeated election opponent, former general Prabowo Subianto who has alleged widespread ballot-rigging, also appealed for calm.

Prabowo, who says he plans to challenge the election result in the Constitutional Court, urged supporters gathering in Jakarta to act wisely. "Avoid violence. And end your actions even though they are peaceful," he said in a statement. "I call for you to go home."

Protesters clash with Indonesian riot police during a demonstration in front of the Elections Supervisory Agency on May 22, 2019 in Jakarta, Indonesia after the official government election results were announced.

On Tuesday, the General Elections Commission said Widodo had won 55.5% of the vote, securing a second term as leader of the world's third largest democracy.

Six people died and another 200 were injured in the protests on Tuesday, according to Jakarta's Governor Anies Baswedan.

Over 250 people have been arrested for instigating riots, national police commissioner Argo Yuwono said Wednesday, adding that police had seized fireworks, a sickle, arrows, petrol bombs and envelopes with names on containing rupiah currency.

Cars after an overnight demonstration by the Elections Oversight Body in Jakarta on May 22, 2019.

Australia warned Thursday of a continuing risk of violence in the capital, including acts of terrorism.

Public transport, cultural sites and some schools remained closed, the Department of Foreign Affairs and Trade said in an advisory.

Authorities had been preparing for possible unrest after the announcement of the election result -- there was already heavy security and barbed-wire barricades in place in Jakarta on Tuesday.

Indonesian anti-riot police take a position to disperse the mob during an overnight violent demonstration near by the Elections Oversight Body in Jakarta on May 22, 2019.

A long rivalry

This year's election was the second time Widodo and Prabowo have faced off.

The pair went head-to-head in the 2014 election, when there was a feeling that democracy itself was at stake. At the time, Prabowo indicated that he would roll back democratic reform, while Widodo, a self-styled man-of-the-people with no links to the military or the country's traditional elite, promised to protect hard-won gains.

After losing that vote, Prabowo slammed the election commission, citing "massive, structural and systematic cheating," but the Constitutional Court upheld Widodo's victory.

Indonesia's 2019 election was billed as one of the most complicated single-day ballots ever undertaken. For the first time, the country held its presidential, legislative elections and local elections on the same day, with more than 245,000 candidates running for over 20,000 seats.

Some 193 million people were eligible to vote across the archipelago's 17,000 islands, and more than 800,000 polling stations and six million election workers were involved.