Seoul, South Korea(CNN) South Korea believes its neighbor to the north may be able to mount a nuclear warhead onto a medium-range missile.
In a background briefing with foreign reporters Tuesday, a government official said it appears North Korea has succeeded in miniaturizing a warhead enough to be mounted onto a Rodong missile.
The official -- who remains unnamed as per South Korean government protocol -- says this ballistic missile can deliver a one ton (907 kg) warhead a distance of 2,000 km (1243 miles), putting U.S. military bases in South Korea and Japan within range.
The official said: "We believe they have the ability to mount a nuclear warhead on a Rodong. Whether they will fire it like that is a political decision."
However, the official added they have no evidence to prove this capability, an assessment backed up by the United States.
"We know that they've said they have that capability and we have to take them at their word," Pentagon Spokesman Captain Jeff Davis told reporters Tuesday. "But we have not seen them demonstrate it."
How North Korea's nuclear program went from threats to reality
Nuclear plans progressing
North Korea's verbal volleys
North Korea has a history of using creative language to express loathing for its enemies. Here are some of the regime's more colorful threats against the West.
March 2016: North Korea warned it would make a "preemptive and offensive nuclear strike" in response to
joint U.S.-South Korean military exercises. Pyongyang issued a long statement promising that "time will prove how the crime-woven history of the U.S. imperialists who have grown corpulent through aggression and war will come to an end and how the Park Geun Hye group's disgraceful remaining days will meet a miserable doom as it is keen on the confrontation with the fellow countrymen in the north."
March 2016: Following the imposition of strict U.N. sanctions, North Korean leader Kim Jong Un said the country's "nuclear warheads need to be ready for use at any time," the North Korean state news agency KCNA reported.
January 2016: North Korea claimed to have successfully tested a thermonuclear weapon, justifying its right to have an H-bomb on the grounds of "self defense."
September 2015: In a statement, North Korea said its nuclear arsenal was ready for use "at any time."
August 2015: As forces from the U.S. and South Korea took part in joint military drills. North Korea's state media referred to the exercises, which started on August 17, as "madcap" and issued a stern warning to America: "If the U.S. ignites a war in the end, far from drawing a lesson taught by its bitter defeat in the history, the DPRK will bring an irrevocable disaster and disgrace to it."
August 2015: On August 23, as North Korean negotiators were meeting with their South Korean counterparts over current tensions, a KCTV presenter appeared on air repeating North Korea's ambitions to "destroy the warmongering South Korean puppet military."
December 2014: The
FBI said it suspected North Korea was behind a hack of Sony Entertainment, which led executives to initially cancel the theatrical release of "The Interview." The film was a comedy about an American television personality who the CIA asks to assassinate North Korean leader Kim Jong Un.
North Korea threatened "merciless" action against the U.S. if the film was released, accusing the U.S. of retaliating for the hack by shutting down North Korea's Internet access. North Korea's National Defense Commission
also called U.S. President Barack Obama "reckless" and a "monkey."
July 2014: North Korea threatens to hit the White House and Pentagon with nuclear weapons. American "imperialists threaten our sovereignty and survival," North Korean officials reportedly said after the country accused the U.S. of increasing hostilities on the border with South Korea. "Our troops will fire our nuclear-armed rockets at the White House and the Pentagon -- the sources of all evil," North Korean Gen. Hwang Pyong-So said,
according to The Telegraph.
March 2013: Angered by tougher U.N. sanctions and joint military exercises by the United States and South Korea, the
Supreme Command of North Korea's military vowed to put "on highest alert" the country's "rocket units" that are assigned to strike "U.S. imperialist aggressor troops in the U.S. mainland and on Hawaii and Guam and other operational zone in the Pacific." Whether Pyongyang has the will to back up such doomsday talk is a perplexing question,
but there is evidence that its know-how -- in terms of uranium enrichment, nuclear testing and missile technology -- is progressing.
February 2013: In a message to the United States and South Korea,
North Korea vowed "miserable destruction" if "your side ignites a war of aggression by staging reckless joint military exercises."
June 2012: Once again, North Korea
vowed to be "merciless" in its promised attack on the United States, this time threatening a "sacred war" as it aimed artillery at South Korean media groups. North Korea
was mad that South Korean journalists had criticized Pyongyang children's festivals meant to foster allegiance to the Kim family.
April 2012: North Korea's state-run news agency
reported that "the moment of explosion is approaching fast" and promised "merciless" strikes against the United States. "The U.S. had better ponder over the prevailing grave situation," it said. Later that month, Pyongyang
launched a long-range rocket that broke apart and fell into the sea. The launch came during preparations for a grand party that celebrated the 100th anniversary of the birth of Kim Il Sung, the founder of North Korea.
November 2011: North Korea's
military threatened to turn the capital of South Korea into a "sea of fire," according to South Korea's Yonhap News Agency.
2009: After the U.S. pledge to give nuclear defense to South Korea,
Pyongyang threatened a "fire shower of nuclear retaliation."
2002: U.S. President George W. Bush includes North Korea in an "axis of evil" with Iran and Iraq, which North Korea brushes off as a "little short of a declaration of war." North Korea reportedly
threatened to "wipe out the aggressors." That year, North Korea also threatened to
kick out international inspectors who were in the country to monitor its compliance with global nuclear nonproliferation agreements.
Kim Jong Un claimed last month his country had successfully miniaturized a nuclear weapon, as state run media published photos of him next to what it said was the miniaturized warhead.
The briefing came as Washington D.C.-based monitoring project 38 North said that it had logged "suspicious activity" at the North's Yongbyon nuclear facility.
Pyongyang carried out its fourth nuclear test on January 6th and has insisted its nuclear program will continue despite further U.N. sanctions passed against the country last month.
The South Korean government official said the focus now should be on implementing these sanctions, adding there may be a level of chaos in the country when the cash starts to dry up but "at this point the leadership of Kim Jong Un is seemingly unshakeable."
Meanwhile, Seoul says recent GPS disruptions carried out by the North ended Tuesday afternoon.
The Ministry of Science, ICT and Future Planning says they traced the jamming to five different areas in North Korea originating on March 31. The ministry says 962 airplanes, 692 ships and 1,785 communication network base stations were affected but no damage reported.
North Korea has not responded to the South's accusation.