Jakarta. Police confirmed on Wednesday evening the arrest of nearly 260 protesters participating in the May 22 rally against the result of last month's presidential election, after rioting broke out at three locations in Central and West Jakarta.

They were arrested outside the offices of the Election Supervisory Agency (Bawaslu) and in Gambir, both in Central Jakarta, and in Petamburan, West Jakarta.

"There are 257 suspects who were arrested at the three crime scenes," Jakarta Police spokesman Chief Comr. Argo Yuwono Argo said.

He said those arrested near the Bawaslu offices attacked police officers, destroyed property and tried to force their way into the building.

The suspects arrested in Petamburan allegedly attacked a police dormitory, damaged property and set cars alight, while those arrested in Gambir reportedly attacked a police station and dormitory.

Police found black flags, firecrackers, stones, arrowheads, sickles, mobile phones, Molotov cocktails and envelopes stuffed with cash in the three locations.

"They were ordered [to cause a riot]. There is money in envelopes. There are others who have orchestrated the events," Argo said, adding that there were also names inside the cash envelopes.

The amounts of cash inside the envelopes varied from Rp 200,000 to Rp 500,000 ($14-$35). Police also seized Rp 5 million and $2,760 in cash in separate finds.

Argo said the suspect found with US dollars came from Bima in West Nusa Tenggara, while the Rp 5 million was given to one of the suspects to use as operational funds.

"[The events] were planned, organized; there are funders. Objects were prepared, such as in Petamburan, where rocks and arrowheads were left on the side of the road, in preparation for the protestors' arrival," he said.

Most of the suspects originate from outside Jakarta and are unemployed. Police earlier said they were mainly from Banten, West Java and Central Java.

"Those from West Java went to Sunda Kelapa [in North Jakarta] where they met with several people we are still looking for. They then planned the attack on the police dormitory in Petamburan," Argo said.

Some of the suspects coordinated with and provoked others to join the rioting through a WhatsApp group.

The suspects are facing multiple charges under the Criminal Code, with a maximum penalty of 12 years in prison.

Those who were involved in the riot in Petamburan face an additional charge under Article 187 of the Criminal Code, which carries a maximum penalty of 20 years' imprisonment.

Clashes between security forces and protesters were continuing in two locations in Jakarta on Wednesday evening.