Newly-released commercial satellite imagery suggests North Korea is continuing to develop ballistic missile sites at more than a dozen locations, amid stalled discussions over the country's nuclear weapons program between North Korea and American diplomats.

The US State Department commented on the issue, saying: "Should Chairman Kim follow through on his commitments, including complete denuclearisation and the elimination of ballistic missile programs, a much brighter future lies ahead for North Korea and its people".

North Korea declared its nuclear force "complete" and halted missile and nuclear bomb testing earlier this year, but USA and South Korean negotiators have yet to elicit from Pyongyang a concrete declaration of the size or scope of the weapons programs, or a promise to stop deploying its existing arsenal. He has said sanctions would stay in place until North Korea disarmed, but that he was "no rush" to force the pace of disarmament.

He also said it would not be appropriate to call the undeclared missile sites a "deception" by North Korea, as worded by numerous US media, since the North has not yet agreed to dismantle its missile bases, nor is the regime tied to a treaty or a deal to do so.

Trump's June meeting in Singapore with Kim in the first-ever summit between the two countries that never formally ended the 1950-53 Korean War.

However, in recent weeks, negotiations have cooled down as Pyongyang considers that it has already taken several steps but has not had the expected response from Washington, which has neither relaxed the sanctions nor cancelled its joint military manoeuvers with South Korea, something North Korea considers a provocation.

"Our government will participate in the adoption of the resolution under the basic principle to make joint efforts with the global community for the human rights of North Korean people to be addressed substantively as a universal value of mankind", Kim said at a press briefing.

The secret missile bases are, notably, not launch sites.

Although not designed as launch sites, the bases could be used to launch short-range as well as intercontinental ballistic missiles.

They are created to enable mobile missile launchers to quickly exit the underground facilities and move to previously prepared launch sites.

US Secretary of State Mike Pompeo had been scheduled to meet Kim's right-hand man, Kim Yong Chol, in NY last week to discuss denuclearization efforts and prepare for a possible second summit, according to the State Department. Pyongyang said however that it is still interested in pursuing talks and describes Trump as being a more amenable interlocutor than other U.S. officials.

Medium-range missiles capable of striking Japan and all of South Korea reportedly are deployed in an operational belt 55 to 100 miles (90 to 150 kilometers) north of the demilitarized zone.

Within the Japanese government, many believe that North Korea will not completely abandon its nuclear ambitions if the United States does not exert strong pressure on Pyongyang.