A member of the police bomb squad unit approaches the scene of an explosion following an attack on a police box in central Jakarta, Jan. 14, 2016, in this photo taken by Antara Foto. REUTERS/M Agung Rajasa/Antara Foto

The five Islamic State militants behind Thursday's gun and bomb assault on Jakarta had planned to launch attacks on other Indonesian cities with the help of at least 12 others, police said on Saturday.

The five were killed in the Jakarta attacks and police have arrested 12 others connected to the assault.

"There were general plans targeting certain places like police and government offices, foreigners or those cooperating with foreign entities," police spokesman Anton Charliyan told reporters.