Indonesian police fired tear gas to disperse demonstrators in downtown Jakarta with at least six people killed during a rally opposed to President Joko Widodo’s re-election.

The country’s election commission has today released official results that confirmed Widodo, 57, had beaten retired military general Prabowo Subianto for the presidency in a poll held on April 17.

Police sirens blared as fresh skirmishes broke out with thousands of protesters chanting and waving Indonesian flags in the heart of the capital.

Some hurled stones and fireworks at riot police who lined up behind a razor wire barricade near the election supervisory agency building.

At least three officers were injured in the clashes and carried away.

National police chief Tito Karnavian said six people had died, but denied authorities had fired live rounds at protesters, and called for calm.

“Some had gunshot wounds, some had blunt force wounds but we still need to clarify this,” he told reporters.

Jakarta’s governor Anies Baswedan said on Wednesday morning that about 200 had been injured.

Subianto has said he would challenge the results in court, and warned that his claims of widespread cheating could spark street protests.

Several thousand people rallied in support of Subianto near the election supervisory agency office in the heart of the capital Jakarta today.

The protest ended peacefully, but police in riot gear later fired tear gas at some demonstrators who refused to leave the area and hurled fireworks and other objects at police.

Earlier, some protesters had set market stalls on fire.

It was not immediately clear if any demonstrators or police were injured in the clash.

More than 30,000 troops were deployed across the capital in anticipation of protests after the official election results were published.

Tensions have also spiked since police said last week that they had arrested dozens of Islamic State-linked terror suspects who had planned to cause chaos by bombing post-election protests.

Last month, a record 245,000 candidates ran for public office in Indonesia’s elections, from the presidency and parliamentary seats to local positions — the first time all were held on the same day.