(CNN) At least 47 people were killed and dozens others injured in a fireworks factory explosion near the Indonesian capital of Jakarta on Thursday.

Regional police spokesman Argo Yuwono said 103 workers were believed to be in the building at the time of the blast and that 10 remained unaccounted for, according to CNN Indonesia, a CNN affiliate.

"We don't know, however, if those 10 workers were actually in the factory at the time, or whether they may have been ill and not come to work," he said.

Indonesian forensic police at the scene of the explosion on Thursday.

Thirty-four others were injured and have been taken to hospital, local police official Freddy Yudha said earlier.

Officials said that a large explosion took place, followed by a smaller one, and that a fire then broke out, leaving some of the victims with burns.

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