While discussions continued in an attempt to de-escalate the Korean border conflict, South Korea claims it is detecting suspicious troop movements in the North.
The report comes on the heels of North Korean state media proclaiming that one million citizens have offered to defend North Korea if aggression breaks out with South Korea.
The Korean Central News Agency reported, "Young people across the Democratic People's Republic of Korea are turning out in the sacred war for defending the country with their faith and will to annihilate the enemies."
Suspicion between the two countries is at all-time highs after an exchange of artillery on Thursday.
Over the weekend senior level officers from South Korea held round the clock meetings with North Korean top executives in a bid to quell the current state of affairs.
South Korea's office of the president said that the discussions had started again for a second day as of Sunday.
Delegates failed to strike a deal on Saturday in talks that went well into the night.
According to Seoul, the North fired the first shot, aimed at huge speakers which have been preaching propaganda across the boundary from South Korea.
North Korea has continued to deny the allegations.
The loudspeakers were installed after two South Korean military officers were injured by landmines while patrolling the demilitarized region. South Korea accused the North of planting fresh landmines, something the North refuted.
A South Korean news organization said that Kim Jong-Un announced a "quasi-state of war" on Thursday after holding an crisis meeting of the communist nation's armed forces leaders.
South Korea's armed forces said on Sunday that it has sensed suspicious submarine and troop movements in North Korea that imply Pyongyang could be considering a strike.
Approximately 70% of North Korea’s 77 submarines have departed from their bases, the armed forces said.
A South Korean officer also said that the North had enhanced the strength of its vanguard artillery forces.
Many inhabitants have been evacuated from some South Korean villages near the border.
Notoriously tight lipped UN Secretary-General Ban Ki-moon, a citizen of South Korea, urged both sides to get the situation under control.