The Jakarta police have arrested 257 rioters involved in violent election demonstrations and more are expected to be arrested as the demonstrations are still going on, Jakarta police spokesperson Argo Yuwono said here on Wednesday.

"Those rioters were arrested in the last two days in Gambir, Petamburan and around the Bawaslu building," Argo told a press conference in his office.

He said the rioters involved in clashes with police are apparently from different groups with supporters of the defeated presidential candidate Prabowo Subianto.

The spokesperson said the rioters had been paid to incite chaos and carry out aggressive acts against the police.

"We suspect their acts have been well-planned."

Police confiscated money, stones, Molotov cocktails, machetes and cellphones from the arrested rioters.