Photo/Illutration A Hwasong 14 intercontinental ballistic missile on a mobile launcher in July 2017 (From North Korea’s Rodong Sinmun website)

North Korea is busy constructing dozens of concrete platforms for mobile missile launchers as it raises the ante in denuclearization talks with Washington, according to defense sources in the United States and South Korea.

The sources said the work got under way this summer at dozens of sites.

Japanese and South Korean authorities expressed concern about Pyongyang’s latest attempt to heighten military tensions in the region to wrest concessions from Washington in stalemated denuclearization talks.

Construction of the platforms apparently reflects fears that launchers could become dysfunctional or missile trajectories veer off track due to the soft ground on which they are installed.

The program is also intended to prevent other countries from detecting where missiles will be launched.

The platforms, each dozens of meters in width and length, are large enough for mobile launchers to fire intercontinental ballistic missiles, according to the sources.

An analysis of satellite images of the sites and photos of previous missile launches released by Pyongyang suggest that some launch sites have become compromised and some mobile launch vehicles were damaged in past launches due to strong vibrations, according to an intelligence assessment by Japan, the United States and South Korea.

In other instances, Pyongyang was forced to place mobile launchers on a paved expressway or airport runway to secure a solid base for the vehicle.

North Korea last conducted an intercontinental ballistic missile test in November 2017 when it launched a Hwasong 15 (Mars 15) projectile capable of targeting the U.S. mainland.

The regime headed by Kim Jong Un apparently decided against provoking the Trump administration in hopes of making progress in bilateral negotiations.

A second summit between Kim and President Donald Trump in Hanoi in February collapsed as the two sides were unable to narrow differences over their respective demands.

Kim, in an address in April, pledged to patiently wait until the year-end for new initiatives from Washington to break the impasse.

North Korea, apparently frustrated by the lack of progress, has tested short-range ballistic missiles and rockets on 13 occasions since May.

North Korea’s chief nuclear negotiator, Kim Myong Gil, said Nov. 19 that reopening dialogue with Washington will be difficult unless the United States abandons its policy of hostility toward the reclusive country, according to the state-run Korean Central News Agency.

Pyongyang has said it could take a “new path” if the United States fails to make concessions by the end of this month.

South Korea’s National Intelligence Service suspects North Korea may test an intermediate-range or longer-range ballistic missile in coming weeks, according to the sources.

Japan’s Maritime Self-Defense Force has deployed Aegis destroyers in the Sea of Japan since early November to prepare for further provocations from Pyongyang.