North Korea on Monday threatened to resume propaganda loudspeaker broadcasts and deploy additional weapons along its border with South Korea, as the two rivals remain locked in a dispute over last month's landmine explosions that injured three South Korean soldiers.
Earlier this month, South Korea formally accused North Korea of planting the mines that exploded on Sept. 21, urging Pyongyang to apologise and remove other mines. The announcement came after North Korea denied responsibility for the blasts and warned of strong retaliation if provoked.
On Monday, Kim Yo Jong, the influential sister of North Korean leader Kim Jong Un, accused South Korea of repeatedly firing warning shots and issuing warning broadcasts along the border since August, citing alleged crossings by North Korean soldiers as an "unreasonable pretext."
She said such provocations had "gone beyond the red line" since the landmine explosions.
"A grave situation is prevailing along the southern border due to the reckless behavior of the ROK military gangsters," Kim Yo Jong said, referring to South Korea by its official name, the Republic of Korea.
She said the North Korean military was considering deploying "more tactical strike means along the southern border as a preemptive and suppressive measure to deal with contingency" and resuming loudspeaker broadcasts against South Korea.
On Tuesday, South Korea's Joint Chiefs of Staff chairman, Jin Yong-Sung, described the North Korean threats as "intolerable" and ordered the military to respond firmly to any potential provocations.
Jin said South Korea's military would firmly deal with any incursions by North Korean troops across the border, according to the Joint Chiefs of Staff.
Tensions along the Korean border, one of the world's most heavily fortified, have risen in recent years as North Korea has added landmines, barbed-wire fences, anti-tank barriers and other frontline fortifications under its policy of severing ties with South Korea.
South Korea's military previously said North Korean soldiers had crossed the Military Demarcation Line 50 times this year while carrying out fortification work. Seoul said its forces responded by firing warning shots and issuing warning broadcasts. The military did not immediately respond to North Korea's latest warning.
In 2015, landmine explosions blamed on North Korea that maimed two South Korean soldiers brought the two Koreas to the brink of armed conflict after Seoul resumed frontline propaganda loudspeaker broadcasts for the first time in 11 years.
The broadcasts are among the traditional psychological warfare tactics dating back to the Cold War that the two Koreas have occasionally used against each other during periods of confrontation.
Since taking office last year, South Korea's liberal government, led by President Lee Jae Myung, has halted the broadcasts as part of efforts to improve relations with North Korea. Pyongyang subsequently stopped its own broadcasts.
North Korea has recently intensified its weapons testing, apparently seeking to pressure the United States into making greater concessions after US President Donald Trump renewed efforts to restore diplomatic engagement with Kim Jong Un.