Does the National Army have police powers in the DR and if so why?

I frequently see or hear about soldiers performing police duties in the DR. In fact, I remember relatives of mine who were in the army and were allowed (and possibly still are) to carry their service weapon as a military service member out in the civilian world.

I guess having been out of the country since my childhood has definitely had its effect on my thinking and how I perceive things 'should be.' So if there's anyone here who cares to elucidate yours truly on the thinking behind or the law that promotes this type of doctrine on the part of the government of the DR, I'll be forever grateful.

Personally, I think civilian authorities should be the only ones allowed to carry firearms during peacetime. Is the mission of the Dominican Army defined in such a way that requires them to always be armed in the streets? If I'm wrong, someone please correct me.

Thanks.