North Korean leader Kim Jong Un has replaced three top officials in charge of his personal security, Seoul said Tuesday, a sign the despot may increasingly fear assassination plots.Seoul's Unification Ministry responsible for managing relations with Pyongyang said three state agencies handling Kim's security had new bosses.The reshuffle was spotted during a military parade in October, the ministry said.The changes at the Bodyguard Command in particular, which handles security measures against drone or electronic attacks, could be linked to Kim's decision to send troops to aid Russia's war in Ukraine, an expert said.