President Park Geun-hye on Monday ordered the military to maintain strong readiness against North Korea's constant threats, asserting that its land mine attack earlier this month was a "clear military provocation" intended to kill South Korean soldiers.
Park made the comments at a Cabinet meeting in an underground bunker to mark the launch of the Ulchi exercise, a four-day pan-national drill against contingencies.
A joint military Ulchi Freedom Guardian exercise with the US was also launched for a 12-day run. The military drill has been lambasted by the North, which fears it is a rehearsal for an invasion.
"We need to maintain strong military readiness to protect our people's lives and their properties from North Korea's provocations and to keep peace on the Korean Peninsula, at a time when military threats posed by North Korea are on the rise," Park said.
Cross-border tension is expected to escalate in the coming weeks, following the North's Aug. 4 land mine attack in the DMZ that injured two South Korean soldiers, and as the North threatens to take military action unless the two allies halt their annual exercise.
The South Korean president also praised the injured soldiers, saying they were brave examples of the military's commitment to serving the nation. She wished the two well and requested officials to take every possible means to treat them and seek ways to honour their actions.
Pyongyang has denied its role in the incident, countering Seoul's announcement that North Korea planted the mines inside the demilitarized zone by illegally crossing the border.
Last week, South Korea resumed loudspeaker broadcasts in the Demilitarized Zone, more than 11 years after the two sides halted such psychological tactics in 2004, to protest against Pyongyang's land mine attack.
In apparent retaliation to Seoul's propaganda programme, North Korea on Monday afternoon launched a loudspeaker campaign at the border.
"We have learned that North Korean Army has resumed loudspeaker broadcasts at some areas of the eastern border," said a South Korean Army official.
North Korea on Sunday vowed to retaliate against the US and urged South Korea to halt the joint military exercise if it wants to hold inter-Korean talks.
Seoul and Washington, meanwhile, have refuted the North's claim, saying that the exercise is defensive in nature.
South Korean Defence Minister Han Min-koo and visiting US Undersecretary of Defence for Policy Christine E. Wormuth said over the weekend that the combined exercise is meant to protect the region and maintain stability on the Korean Peninsula.
Inter-Korean tension has been surging despite initial hopes that the rigid relations would thaw on the occasion of the 70th anniversary of Liberation Day last Saturday.
North Korea on Sunday denounced Park's Liberation Day speech, rejecting her offer of holding reunion events for separated families.
The Committee for the Peaceful Reunification of Korea said in a statement that Park's speech "viciously" slandered the North and that she drove into catastrophe.
In her speech, Park had said that Seoul "will sternly deal with any North Korean provocations" that will only further deepen Pyongyang's isolation and destruction.
Seoul's Unification Ministry, in return, expressed strong regret over the North's statement, urging it to return to dialogue.
"The government strongly condemns North Korea for making the preposterous argument that the recent mine incident is a fabricated slander against the North," the ministry said in a statement.
"The North should discard its irresponsible manner, which betrays the historical significance of Liberation Day. … We once again urge the North to alleviate military tension, build trust and head for peaceful unification as proposed by the South through dialogue and co-operation," it added.