Moscow  - Japan scrambled four fighter jets on Wednesday to flank Russian bombers on a long-range patrol over the Sea of Japan, a Russian air force official said.

"Four Japanese air force F-15 fighters escorted the long-range aviation crews as they flew over the Sea of Japan," Lieutenant- Colonel Vladimir Drik was quoted by news agency Interfax as saying.

Russia ordered out an extra two Russian Su-27 fighters to backup their TU-22 bombers, known as Backfires by their NATO codenames, while they completed their training, Drik said.

The exercises over the Sea of Japan were part of Russia's largest-ever military manoeuvres this month, dubbed Stability 2008, involving tens of thousands of servicemen and all of Russia's nuclear forces.

Former President Vladimir Putin relaunched Soviet-era long-range patrols last year as part of his drive to modernize and retrain Russia's military, poorly funded and in disarray after the fall of the Soviet Union in 1991. (dpa)