ABC News August 21, 2018

North Korea has not stopped nuclear activities: UN watchdog

WATCH: Bolton: '4 countries' could interfere in midterm elections

North Korea’s nuclear activities have not stopped over the past year and it continues to develop its nuclear program, the UN’s nuclear watchdog said in a new report.

The "continuation and further development" of the program are "cause for grave concern," the International Atomic Energy Agency said in its report, released Monday, which covered developments since August 2017 and found that the North had carried out "clear violations of relevant U.N. Security Council Resolutions."

KCNA VIA KNS/AFP/Getty Images, FILE
This undated picture released from North Korea's official Korean Central News Agency (KCNA), Sept. 16, 2017, shows North Korean leader Kim Jong-Un (C) inspecting a launching drill of the medium-and-long range strategic ballistic rocket Hwasong-12 at an undisclosed location.

The report, issued by IAEA Director General Yukiya Amano, noted that the agency faced challenges in what it could actually verify.

(MORE: Ahead of cross-border family reunion, South Koreans express anticipation)

"As the Agency remains unable to carry out verification activities in the DPRK, its knowledge of the DPRK’s nuclear programme is limited and, as further nuclear activities take place in the country, this knowledge is declining," the report said, using the acronym for North Korea's official name, the Democratic People's Republic of Korea.

Photo DigitalGlobe/38North via Getty Images, FILE
In this file photo, a satellite image of the 5 MWe Reactor at Yongbyon Nuclear Complex in North Korea is seen on Nov. 13, 2012.

Without access to major nuclear sites in North Korea, the IAEA said it has relied in part on satellite imagery and open-source information.

(MORE: Trump adviser: Russia, China, North Korea and Iran could meddle in US midterms)

President Donald Trump met with North Korean leader Kim Jong Un in Singapore on June 12 and the next day declared in a tweet, "There is no longer a Nuclear Threat from North Korea."

Saul Loeb/AFP/Getty Images
North Korea's leader Kim Jong Un walks with President Donald Trump, left, during a break in talks at their historic US-North Korea summit at the Capella Hotel on Sentosa island in Singapore, June 12, 2018.

The president repeated the claim in an interview with Reuters published Monday, "I stopped [North Korea’s] nuclear testing. I stopped [North Korea’s] missile testing."

In its report this week, the IAEA called North Korea's continued nuclear activity "deeply regrettable" and called on the the country to cooperate and fulfill its obligations under U.N. Security Council resolutions.

KCNA via AFP/Getty Images, FILE
This picture taken on July 4, 2017 and released by North Korea's official Korean Central News Agency (KCNA) on July 5, 2017 shows the successful test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location.