Kim Jong Un meets scientists and technicians in the field of nuclear weapons research in this photo released on March 9, 2016. State-run media claimed the object the North Korean leader posed with is a miniaturized nuclear warhead.

Outside analysts say the round object appears to be a model of a warhead part. It remains unclear whether the country has functioning miniature warheads or is just trying to develop one.

Kim Jong Un reacts as he watches a long range rocket launch in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang, February 7, 2016.

Kim Jong Un inspects the newly built combined service boat Mujigae in this photo released on September 28, 2015.

Kim Jong Un watches a long range rocket launched into the air in this still image taken from KRT footage and released by Yonhap on February 7, 2016.

Kim Jong Un poses during a photo session with emotional participants in the Second Meeting of KPA Exemplary Servicemen's Families in this photo released in Pyongyang December 9, 2014.

Kim Jong Un guides Korean People's (KPA) military drills in Pyongyang in this photo released on February 21, 2016.

North Korean leader Kim Jong Un offers advice at the Korean People's Army's (KPA) February 20 Factory, which produces foodstuff, in this photo released in Pyongyang on November 15, 2014.

North Korean leader Kim Jong Un greets Korean People's Army pilots during a visit to the summit of Mt Paektu April 18, 2015, in this photo released on April 19, 2015.

North Korean leader Kim Jong Un poses for pictures with female pilots as he provides field guidance for the flight drill of female pilots of pursuit planes of the KPA Air and Anti-Air Force in this photo released in Pyongyang, November 28, 2014.

NBA star Dennis Rodman poses with Kim Jong Un in Pyongyang in a photo released January 2014.

Rodman sang "Happy Birthday' to the supreme leader during an exhibition basketball game in a stadium in the North Korean capitol during his visit.

North Korean leader Kim Jung Un guides the test fire of a tactical rocket in this photo released in Pyongyang, August 15, 2014.

North Korean leader Kim Jong Un (C) looks through a periscope of a submarine during his inspection of the Korean People's Army (KPA) Naval Unit 167 in this photo released in Pyongyang, June 16, 2014.

North Korean leader Kim Jong Un gives field guidance to Farm No. 1116 under the Korean People's Army (KPA) Unit 810 in this photo released in Pyongyang, August 13, 2015.

North Korean leader Kim Jong Un (front) stands on the conning tower of a submarine during his inspection of the Korean People's Army (KPA) Naval Unit 167 in this photo released in Pyongyang, June 16, 2014.

Kim Jong Un looks through a pair of binoculars during an inspection of the Hwa Islet Defense Detachment standing guard over a forward post off the east coast of the Korean peninsula, in this photo released on July 1, 2014.

North Korean leader Kim Jong Un smokes a cigarette at the General Satellite Control and Command Center after the launch of the Unha-3 (Milky Way 3) rocket carrying the second version of Kwangmyongsong-3 satellite at West Sea Satellite Launch Site in Cholsan county, North Pyongan province, December 12, 2012.

North Korean leader Kim Jong Un visits the newly built workers' hostel of Kim Jong Suk Pyongyang Textile Mill in this photo released on April 30, 2014.

North Korean leader Kim Jong Un smiles during a visit to the Chonji Lubricant Factory in this photo released on August 6, 2014.

North Korean leader Kim Jong Un provides field guidance during his visit to the Wonsan Shoe Factory in this photo released on July 26, 2014.

North Korean leader Kim Jong-un inspects the 507th unit of the Korean People's Army and sentry guards at Mount O-sung in this photo taken June 2, 2013 and released on June 3, 2013.

Kim Jong-Un visits the Mangyongdae Revolutionary School during the Lunar New Year holidays in Pyongyang, in this picture released on January 25, 2012.

North Korea leader Kim Jong Un looks at bottles of alcohol as he visits the Changsong Foodstuff Factory, in this photo released on June 14, 2013.

Kim Jong Un inspects the construction site of apartment houses for scientists close to completion in this photo released on August 7, 2013.

Kim Jong Un looks at a biscuit as he provides field guidance at Foodstuff Factory No. 354 of the Korean People's Army in this photo released on November 17, 2013.

Kim Jong Un visits the Designing Institute of the Korean People's Army in this photo released on December 14, 2013.

Kim Jong Un looks at the latest combat and technical equipment, made by unit 1501 of the Korean People's Army, during his visit to the unit March 24, 2013.

North Korean leader Kim Jong Un visits the now under construction Breeding Station No. 621 of the Korean People's Army at an undisclosed location in this picture released on May 21, 2013.

Kim Jong Un watches a night naval fire strike drill in this undated photo released June 16, 2015.

Kim Jong Un watches what the country's Korean Central News Agency (KCNA) says is a test-fire of a strategic submarine underwater ballistic missile in this undated photo released by KCNA in Pyongyang May 9, 2015.