"The bomb was in the form of a five-litre red-coloured jerrycan, which was placed inside a backpack," the chief of Central Sulawesi Regional Police Office, Brigadier General Dewa Parsana, said in an SMS sent from Poso on Tuesday.
While dismantling the bomb, the police found a cellular phone as the timer of the bomb, urea nitrate powder, hundreds of 13-inch nails and two detonators.
Parsana said the bomb was timed to go off at 7.30am local time.
However, a Poso Police Sector Station officer found the bomb at 6.30am, near a security post in front of Poso Central Market, and then reported to the bomb squad of Polres (District Police Office) Poso, which was situated just 200 metres away from the bomb's location.
After the bomb was defused, it was taken to Polres Poso for further investigation.
"We are still investigating and are on the alert," Parsana said.
Previously, on October 22, there was a bomb explosion near a traffic observation post of Polres Poso, in which two people were injured.