First time to see this BMT-72, simply looks great, and that "troop compartment" for 5 persons is great too.
I never heard that this BMT-72 is in service.
Sorry mate, on whole Internet I only find a Chinese site with decent info about this BMT-72, time to start Chinese learning
Anyway here the Chinese Link (Global Military):
http://www.pladaily.com.cn/item/hqjs/huigu/2003-11a.htm
But Chinese classify the BMT-72 not as a real Tank but just a Infantry Combat Vehicle.