Hong Kong (CNN) Police in Hong Kong say they seized and defused two completed bombs stashed at a middle school that could have "killed and injured large numbers of people."

Authorities would not say how they discovered the explosives, nor did they say if the seizure was connected to the more than six months of political unrest that has left the city reeling.

The bombs found Monday night contained a total of 10 kilograms (22 pounds) of high explosives and shrapnel, according to Alick McWhirter, a senior bomb disposal officer with the Hong Kong Police Department's Explosive Ordnance Disposal Bureau (EOD).

He said the two homemade bombs were likely built to be set off by mobile phones and were "complete, fully functional and ready to be used."

"Both of these devices have only one function -- to kill and to maim people," McWhirter said.

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