Two explosions went off near a crowded bus station in the eastern part of the Indonesian capital on Wednesday, police said.
Eyewitnesses reported many casualties.
An eyewitness said that bombs exploded twice near a bus stop facility in Kampung Melayu at about 9 pm.
"The first explosion was very hard and the second one was rather low. I saw several parts of bodies and organs," an eye witness told television.
"I saw some victims were rushed to hospitals," he added.