Authorities fear the toll will rise.
With the operation to contain the attackers still going on, several things were unclear: Exactly how many gunmen were involved, and how many locations they struck.
The U.S. Embassy in Jakarta asked Americans to stay away from the area, saying the "situation continues to unfold."
One of the targets of the Thursday attacks was a police station, next to a busy shopping center, the Sarinah Thamrin Plaza.