At least six people died and 200 were injured as supporters of an unsuccessful presidential candidate clashed with security forces in the Indonesian capital on Wednesday.
The protests erupted after election results showed Mr. Widodo had beaten his long-time rival Prabowo Subianto.
Protests in the capital Jakarta started peacefully on Tuesday but soon turned violent, with cars set on fire and firecrackers thrown at police. Security forces in riot gear fired tear gas to disperse the crowd.
The protestors tried to force their way into the downtown offices of the election supervisory agency late on Tuesday and clashes have continued since then.
The police have said the protests were planned and “not spontaneous”.
Muhammed Iqbal, a spokesman for the police said majority of the protestors came from outside. He also said that the police officers did not use live ammunitions, referring to six dead allegedly by security forces during the protest.
Protestors have been gathering again in the city on Wednesday. President Widodo has promised firm actions against rioters.