How to Increase Police Siren Loudness in PCB Luggage Security System—Amplifier Options?

i have designed luggage security system on PCB.I am sure that all steps have been properly followed like etching,drilling,soldering wihout any short circuit of passive or active component .But inspite of all this voice of police siren from loudspeaker is not so loud to listen if i m sit at 2m distance from PCB.Is there any technical problem?How can i increse the outcome of loudspeaker?Can i use an amplifier?

I am assuming that your present system is working properly in making these comments.
What is the acoustic output from the loudspeaker for a given output power, do you have any data for it. What is the maximum permitted power allowed into the loudspeaker. What power are you presently applying to the loudspeaker. Try placing a power amplifier between the current audio driver and the speaker, taking note of the maximum allowable power output for the speaker, and see if it helps. If you have to use an amplifier, you will possibly have to supply power from higher voltage and capacity batteries. A switching power amplifier is what you will need in the final design for best efficiency if an amplifier is needed, in a bridge configuration. These are available off the shelf as an IC.
Cheers,
Richard

You should use a piezo diaphragm with 10mH choke and buffer transistor. It will be deafening. That's what I use for my luggage alarm.

Please can you post (or link) the circuit diagram you are using, to let us understand it and make helpful suggestions ?