A freakish kinda howling that's freaking me out

For the past few days, there's been a noise outside my apartment that at first sounded like a siren. Then it sounded like someone screaming... and then, I heard a dog barking, which is strange cause there aren't many stray dogs around here, and people don't keep them as pets - cause everyone lives in apartments.

And then I thought of my friend Brian, who told me last year that he lived above a restaurant who.... used to..... slaughter dogs.

So, I'm really not sure what this sound is, but it's a shrilling cry, and I'm having to play my MP3 at a high volume just to drown out the sound.