The Indonesian capital was rocked by a series of explosions and gunfire in the city center on Thursday, in what the police called a terrorist attack.
The police said that at least four people had been killed, and it was feared that the toll would rise.
The attack initially appeared to target a traffic police post at a major intersection, which was heavily damaged by bomb blasts, and at least one police officer was killed by gunfire from an assailant, according to witnesses who spoke to a local television station, TV One.
Gen. Anton Charliyan, a spokesman for the Indonesian National Police, said the attack involved an unknown number of assailants with grenades and guns, at least one of whom was on a motorcycle.
He said no suicide bombers were involved.
Three civilians and a police officer were killed, he said.