The MIG and Sukhoi firms continue to improve designs and upgrade existing equipment.  The Sukhoi Su-35, a modification of the Su-27, is capable of extremely high angles of attack.  Russia has also sold supersonic bombers to Iran and China.   With a combat radius of 1,370 miles, a bombload of 53,000 pounds and nuclear capability, these Tupolev Tu-22M-3 Backfire bombers could upset the balance of power in either the Middle East or Asia.