President Park Geun-hye visited a military base near Seoul Friday to check South Korea's military readiness, Cheong Wa Dae said Friday, after a recent exchange of shells between the two Koreas heightened tensions on the Korean Peninsula.
  

The surprise visit to the headquarters of Third Army in Yogin, Gyeonggi Province, came as North Korea threatened to take military action unless South Korea halts propaganda broadcasts along the heavily fortified border.
  

Park is set to receive a briefing from top military officials on the latest situation, presidential spokesman Min Kyung-wook told reporters.
  

On Thursday, North Korea gave a 48-hour ultimatum for South Korea to end the psychological warfare and dismantle its loudspeakers, otherwise it will launch "a strong military action."
  

South Korea has rejected the North's demand, stoking fears of yet another military clash between the two sides after they briefly exchanged artillery shells over the western section of their border on Thursday.
  

North Korean leader Kim Jong-un has ordered front-line troops to have full combat readiness and front-line areas to be in a "semi-war state" starting at 5 p.m. on Friday, according to the North's state media.
  

South Korea resumed psychological warfare on Aug. 10 in retaliation for a recent land mine attack that left two South Korean soldiers severely injured.
  

South Korea accused the North of planting the mines inside the demilitarized zone that separates the two Koreas, a charge denied by North Korea. (Yonhap)