SHIJIAZHUANG - At least four people were killed and two are missing after a fireworks explosion occurred in Dacheng county, north China's Hebei province, on Friday, according to local authorities.

The blast happened around 4 pm at Zangtun police station where police officers were sampling and identifying fireworks suspected of being illegally traded.

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According to a preliminary investigation, 11 people were at the scene. So far, nine have been rescued, among whom four showed no vital signs, and five are under treatment.

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Local authorities have sent rescuers to search for the missing people. An investigation into the cause of the accident is underway.