When researching Japanese sirens, these 3 recordings always seem to come up (especially the first two). I guess these are Japan's equivalent to the famous HOR Siro Drone recording that is always used in movies. All 3 are different types of Japanese sirens I would assume, though the 2nd also sounds exactly like some types of Russian siren.
https://www.youtube.com/watch?v=e8FO9vJqMzQ
Russian siren that sounds like 2nd siren in videohttps://www.youtube.com/watch?v=LujeVypleP0