Protests in the capital Jakarta on Tuesday started peacefully but later turned violent, with cars set on fire and firecrackers thrown at police, with police in riot gear reacting by firing tear gas to diffuse the crowd.
On Wednesday at a press conference, police did not confirm the figure of those caught up in the chaos given by Governor Anies Baswedan, but said they had received information “that some people were wounded and some died”. It remains unclear what caused the deaths.
National Police Spokesman M Iqbal added that 69 protestors had been arrested following the violence.
“We’re concluding from these events that [these] were not spontaneous masses. They want anarchy, creating riots,” he said.
The protests erupted after election results showed Mr Widodo had beaten his long-time rival Prabowo Subianto.
The Jakarta governor said hospitals would conduct post-mortems to determine the cause of death of those involved.
The country’s General Election Commission confirmed on Tuesday that Mr Widodo had won the presidency, taking 55.5% of votes.
Mr Prabowo who rejected the results on the grounds that he has been cheated.
The ex-general also lost against Mr Widodo at the last election in 2014, and went on to unsuccessfully challenge the results.
More than 192 million people were eligible to vote in the presidential and general elections that took place on 17 April.
Following the announcement of the official results on Tuesday, thousands gathered in front of the election supervisory building in support of Mr Prabowo, but later moved on to other areas across Jakarta after police urged the crowd to disperse.
Local TV stations showed several standoffs between protesters and police in parts of the city.
However, police spokesman Dedi Prasetyo told news agency Reuters that the security officers on the ground were not equipped with live bullets.
More than 30,000 troops had been deployed in Jakarta city in anticipation of potential violence.