The main opposition People Power Party (PPP) on Thursday renewed calls for the government to resume loudspeaker broadcasts along the inter-Korean border to protest against recent mine blasts in the Demilitarized Zone (DMZ), and to replace top security officials here over the incident that left three South Korean soldiers injured. The PPP accused President Lee Jae Myung of failing to take action over the Sept. 21 blasts, which the South Korean military determined to have been caused by mines planted "deliberately" by North Korea. "The president has described North Korea's nuclear weapons as a 'last resort of defense,' even when the North has explicitly stipulated preemptive nuclear strikes under its law on nuclear forces policy," PPP floor leader Jeong Jeom-sig wrote on Facebook. "How can we even consider retaking wartime operational control (OPCON) when the commander-in-chief cannot even tell the difference between an attack and defense, or between a land mine provocation and an 'unfortunate accident?'" he added. Rep. Jeong called for the immediate resignation of Unification Minister Chu