South Korea urged North Korea Tuesday to offer an apology over the deadly landmine attack as Seoul's defense chief vowed to seize initiative along the heavily fortified border.
  

South Korea accused North Korea of intentionally burying three wooden-box land mines on the southern side of the demilitarized zone that separates the two Koreas.
  

Two South Korean staff sergeants were severely injured during a patrol mission on Aug. 4 when the land mines exploded.
  

Presidential spokesman Min Kyung-wook called the incident a clear provocation and a violation of the inter-Korean nonaggression pact.
  

"We urge North Korea to offer an apology over the provocation and punish those responsible for it," Min said.
  

South and North Korea signed a non-aggression pact in 1991. North Korea has since carried out a series of provocations against South Korea, including two deadly attacks in 2010.
  

U.N. Secretary-General Ban Ki-moon also called on the North to stop its provocations and resume dialogue to ease tensions on the peninsula.
  

North Korea should "fully adhere to the obligations under the Armistice Agreement and engage in dialogue on this incident," Ban said in a statement released by the U.N.
  

Defense Minister Han Min-koo said in a meeting with ruling Saenuri Party lawmakers that South Korea's military will carry out an operation to seize initiative in the demilitarized zone, though he did not elaborate.
  

On Monday, South Korea resumed a propaganda loudspeaker campaign along the tensely guarded border for the first time in 11 years in retaliation for the detonation of the North Korean mines.
  

The Koreas halted propaganda loudspeaker broadcasts along their tense border in 2004.
  

North Korea has bristled at South Korea's propaganda campaign that has long been waged by conservative activists and North Korean defectors.
  

For years, North Korean defectors in the South and conservative activists have flown leaflets to the North via balloons to help encourage North Koreans to eventually rise up against the Pyongyang regime.
  

In October, the two Koreas exchanged machine gun fire across the border after the North apparently tried to shoot down balloons carrying anti-Pyongyang leaflets.
  

The 1950-53 Korean War ended in a truce, not a peace treaty, leaving the two Koreas still technically at war. (Yonhap)