MANADO, Indonesia : Twelve people were killed and dozens injured early Sunday after a fire broke out in a crowded karaoke bar in a city on Indonesia's Sulawesi island, police said.

The blaze was sparked by an electrical short-circuit on the second floor of the three-storey Inul Vizta club in the North Sulawesi provincial capital of Manado after midnight. This caused panic among the customers who were singing in private rooms, provincial police spokesman Wilson Damanik told AFP.

"The fire filled the rooms and corridors with thick black smoke and people started panicking and running helter-skelter in the dark. Some inhaled the smoke while others tried to escape by jumping out of the windows onto the street," he said. "So far, 12 people have died, mostly from smoke inhalation," he said, adding they were Indonesians.

He said "dozens" were injured but Indonesian Red Cross official Mahmud Paputungan estimated the number wounded to be around 70.

"Many of them suffered broken bones from jumping from the third storey," Paputungan said.

The blaze was put out and people evacuated to nearby hospitals. Investigations into the cause of the fire were ongoing, Damanik said.

"So far we found that there was no emergency staircase, only one common staircase to access every floor," he said. "So that could be why it was difficult for people to get out quickly. But all these (matters) are still being investigated."

Police were still checking the soot-blackened premises for more possible victims Sunday evening, as curious onlookers gathered.