UPDATE 1-S.Korea scrambled jets to warn Russian warplanes in air defence zone

South Korea scrambled fighter jets on Tuesday to warn Russian warplanes it said had entered its air space identification zone, the latest in a series of such incidents.Seoul's Joint Chiefs of Staff (JCS) said six Russian military aircraft had repeatedly entered the Korea Air Defence Identification Zone (KADIZ) over a six-hour period.An ADIZ, unlike a nation's airspace, is where countries may demand that foreign aircraft take special steps to identify themselves.