North Korea has cleared a 1.8-mile strip of land that extends into the demilitarized zone (DMZ) at the country’s easternmost border, according to NK News analysis of satellite imagery, in an apparent effort to strengthen its south-facing border.

Satellite imagery from Planet Labs shows that the new development appeared in recent weeks and that parts of the construction extend past the DPRK’s final border fence into the DMZ, the 2.5-mile wide boundary between the two Koreas.

Satellite imagery shows that the cleared strip of land was still covered by vegetation as of April 25, indicating that the development occurred in the weeks since.

One significant stretch spans over half a mile inside the DMZ and follows a mountain ridge right in front of South Korea’s Goseong Unification Observatory.

During a visit to the observatory last month, NK News observed North Korean workers wearing military uniforms standing in part of the cleared area. But satellite imagery now shows that the extent of the construction is more extensive than previously known.

In response to questions about the land clearing, the U.N. Command told NK News that “the DPRK has pursued measures to harden its boundaries” recently.

“We are aware of activities inside the DMZ,” the UNC stated, while adding that it “will not comment on specific areas or activities” due to ongoing discussions with the ROK government.

“If the intent of stripping the land is to enable a disparate buildup of military forces, then it would not be allowed,” the UNC continued, but it does “not assess that the intent for this vegetation clearing is to enable such a buildup.”

Steve Tharp, a retired U.S. Army lieutenant colonel who worked at the Joint Security Area for six years, told NK News that military activity inside the DMZ is prohibited under the armistice agreement that ended the 1950-53 Korean War.

He explained that article 13A of the agreement states that both Koreas must “withdraw all of their military forces, supplies and equipment from the demilitarized zone.”

But Tharp noted that both sides have violated these stipulations of the armistice over the years, as South Korea also has armed guard posts inside the DMZ.

South Korea’s Ministry of National Defense declined to comment on the evidence of DPRK construction inside the DMZ in response to NK News inquiries.

The exact purpose of clearing the land inside the DMZ remains unclear, but it comes after North Korean Leader Kim Jong Un ordered officials to revise the “redefine North Korea’s borders” as part of a sweeping policy change rejecting peaceful reunification and emphasizing that the two Koreas are separate countries at war.

The construction follows confirmation that North Korea has been demolishing facilities near major roads connecting to South Korea and reports that the DPRK has also installed landmines at several inter-Korean crossings.

On Wednesday, South Korea’s National Intelligence Service told NK News that North Korea has also “been demolishing parts of the Donghae line” recently, the inter-Korean railway connecting the two Koreas along the East Sea. The line crosses through the section of the DMZ where North Korea is clearing vegetation.

The Donghae Railway featured in inter-Korean talkins during the previous Moon Jae-in administration. Several South Korean technical delegations inspected the North Korean side of the Donghae railway after the two countries agreed to modernize and reconnect the severed train route.

While satellite imagery does not show if North Korea installed weapons in the newly cleared strip of land, Pyongyang announced in November last year that it would “resume all military activities in the DMZ.”

According to Seoul, the DPRK then started rebuilding guard posts and deploying heavy weaponry to the inter-Korean border.

Since then, inter-Korean tensions have continued to be strained. Earlier this week, South Korean President Yoon Suk-yeol formally suspended a 2018 inter-Korean military deal in response to North Korea’s launch of trash-filled balloons to South Korea last week.

South Korea’s defense ministry said the suspension of the Comprehensive Military Agreement allows for the resumption of military operations along the DMZ and near ROK border islands in the Yellow Sea.

Edited by Alannah Hill