January 12, 2008: Russia has begun construction of the first twenty Su-34 fighter-bombers. These will replace the 43 ton Su-24s. The 45 ton Su-34 is yet another variant of the 33 ton Su-27, and is very similar to the 36 ton U.S. F-15E (a two seat fighter bomber version of the 31 ton F-15C.) The Su-34 has a full set of defensive and offensive sensors (radars, targeting cameras, laser designators) and electronic warfare gear, and can carry eight tons of missiles and smart bombs. Russia is buying 58 Su-34s to replace 300 Su-24s (most of these are not fit for service). Over the next two years, Russia plans to put 24 Su-34s in service, at a cost of $36 million each (less than half the cost of an F-15E). Meanwhile, some of the more recently built Su-24s are being upgraded as the Su-24M2. Most of the 1,400 Su-24s built are over 25 years old, and many have been grounded several times recently because of age related problems. The Su-34 has been in the works for several years, and earlier versions of two seater Su-27 bombers were known as the Su-32.