North Korea has been confirmed to have recently started removing parts of the northern section of the Donghae Line, a railway line connecting the two Koreas.

An official at the National Intelligence Service said on Wednesday that the government is closely monitoring the situation as the North appears to be removing railway sleepers from the tracks. 

The inter-Korean Donghae Line, which links South Korea’s Jejin Station in Goseong and Mount Geumgang in North Korea, was connected in 2006 to follow up on the Joint Declaration made between the two Koreas in June 2000. The railway stretches a total of 25-point-five kilometers, with 18-point-five kilometers of the tracks in North Korea and seven kilometers in the South.

In January, North Korean leader Kim Jong-un gave instructions for strict measures to block all channels of inter-Korean communication along the border, such as by cutting off the Gyeongui land route on the North's side to an "irretrievable level."

North Korea then installed mines on the Gyeongui and Donghae roads connecting the two Koreas in January and dismantled street lamps along both roads in March.