SEOUL, South Korea (AP) — South Korea proposed talks with North Korea to clarify the rivals' border line and ease military tensions, saying Monday that North Korean soldiers' repeated border intrusions have raised worries about an armed clash.

South Korea's military says it has been firing warning shots to repel North Korean troops who violated the border's military demarcation line numerous times since they began engaging in work to boost front-line defenses last year. North Korea has denied that and threatened unspecified responses, saying its soldiers worked within the North's territory.

Kim Hong-Cheol, South Korean deputy minister for national defense policy, said Monday that South Korea was offering military talks to prevent an accidental armed clash and lower tensions with North Korea.

Kim said that the North's border intrusions were likely caused by the rivals' different views on the border line, because many of the military demarcation line posts established at the end of the 1950-53 Korean War have been lost.

It's unclear if North Korea would accept South Korea's calls for talks, because it's been shunning all forms of dialogue with South Korea and the U.S. since its leader Kim Jong Un's high-stakes nuclear diplomacy with U.S. President Donald Trump fell apart in 2019. Some observers say South Korea's offer for talks was part of efforts by its liberal government led by President Lee Jae Myung to reopen communication channels with North Korea.

Last year, Kim declared that North Korea was abandoning its long-standing goals of a peaceful unification between the Koreas and ordered the rewriting of the North’s constitution to mark the South as a permanent enemy. South Korea's military said that it has since detected North Korea adding anti-tank barriers and planting more mines at border areas.

The Koreas' 248-kilometer-long (155-mile-long), four-kilometer-wide (2½-mile-wide) border is one of the world’s most heavily armed frontiers. An estimated 2 million mines are peppered inside and near the border, which is also guarded by barbed-wire fences, tank traps and combat troops on both sides. It’s a legacy of the Korean War, which ended with an armistice, not a peace treaty.