The BMPT-72.

via Sputnik

The BMPT-72 is armed with two 30-mm 2A42 automatic cannons that can load ammunition of 850 rounds, four laser-guided Ataka-T anti-tank missile systems and one coaxial machine gun with a remote reloading mechanism.
The vehicle can survive in different climates and zones, including urban areas, and in any light conditions. The Terminator 2 is equipped with night vision, a laser range finder, as well as an integrated laser controlled missile guidance system. It can detect targets within a 5km range, day or night.
Compared to the BMPT, only three crew are used on the BMPT-72, with two grenade launching positions now not required due to automation. The combat weight was also reduced from 47 to 44 tons, with the length and the width standing at 7.2 meters and 3.59 meters, respectively.

Here.

Of all the vehicles that the Russians have, this one would cause me the most concern on the modern battlefield (from an infantry perspective).  If you're in an urban environment and this rolls up, unless you can get a first shot first kill on it then you better have an underground escape route lined up.  Second if you're rolling thru the countryside and this thing shows up it can kill you with its cannons (if you're in an IFV/AFV) or it can sizzle you from long range with its missiles.

Sidenote:  Everyone complains that we get little information on other nations military gear and websites like Sputnik give us looks and then we hear complaints of it all being propaganda.  Amazing.  Quite honestly, and I'm not busting sunshine off the Russians asses, but they're doing what many DoD officials have always said they wanted.  They're being open about many of there defense programs.  So stop complaining, drink in the info and do your best to separate truth from fiction.