South Korean President Lee Jae Myung pledged to "respect" North Korea's political system and said Seoul would not seek unilateral reunification in a speech to mark Liberation Day.

South Korea will end some military activities along its border with North Korea, President Lee Jae Myung said on Friday, in his government's latest effort to improve ties between the neighbouring countries still technically at war.

The 2018 military accord was designed to curb the risk of inadvertent clashes, but broke down after a spike in tensions. The so-called Comprehensive Military Agreement (CMA) signed between the two Koreas was the most substantive deal to result from months of historic meetings between leader Kim Jong Un and then-South Korean President Moon Jae-in.