New Delhi, July 19 -- MOSCOW - Russia's Deputy Foreign Minister Andrei Rudenko warned Sunday that any decision by South Korea to deploy American Typhon missile systems on its territory would be treated as a direct threat to Russian security and would trigger a proportionate response, a formal diplomatic signal directed at Seoul at a moment when the United States is intensifying its effort to position long-range strike capabilities across Asia.

Rudenko's statement, made in an interview with TASS, came with an important qualifier. The Russian Foreign Ministry, he said, currently has no confirmed information that South Korea intends to take this step. The warning is therefore preemptive rather than reactive, a signal from Moscow meant to sh...