When you add these to the mix of advanced surface warships and attack submarines that have recently been entering the Chinese arsenal, you have a triple threat the likes of which the US Navy has not seen since the collapse of the Soviet Union.
http://www.globalsecurity.org/military/world/china/tu-22m.htm
That was a 2004 report, but there has been no mention or notice of the Backfires in China yet. Many wonder if it an actual deal or just the Russians talking at this point.
Time will tell.