Former senior Pentagon official David Shear has expressed strong concern over South Korea's recent decision to withdraw from a military intelligence-sharing pact with Japan, calling the move "an indicator of turbulence."

The 65-year-old former assistant defense secretary for Asian and Pacific affairs recalled that the General Security of Military Information Agreement, concluded in 2016, was seen at the time as marking a "new stage" in Japan-South Korea ties, which have often been marred by wartime historical and territorial disputes.

"We hoped that, as Japan and the ROK improved their defense relationship, that that would put a floor on the broader Japan-ROK bilateral relationship, in other words, it would limit the extent to which that bilateral relationship could deteriorate. We appeared to have been mistaken in that view," Shear said in a recent interview.