Hundreds of North Korean nuclear and missile experts have been collaborating with their Iranian counterparts in more than 10 locations across the Islamic state, a diplomatic source said Sunday.
The revelation lends credence to long-held suspicions that North Korea was helping Iran with a secret nuclear and missile program.
It also represents a new security challenge to the international community as it seeks to curb the nuclear ambitions of Pyongyang and Tehran, and thwart trading of nuclear and missile technology.
North Korea has long been suspected of being behind nuclear and missile proliferation in Iran, Syria, Myanmar and Pakistan.
"Hundreds of North Korean nuclear and missile engineers and scientists have been working at more than 10 sites (in Iran), including Natanz and Qom," the source said, citing human intelligence he declined to identify for security reasons.
The source would not allow the specific number of North Koreans to be published, citing the sensitivity of the intelligence, and would not give further details on the extent of the collaboration. The source spoke on condition of anonymity because of the delicate nature of the issue.
Repeated attempts to contact the Iranian embassy in Seoul by telephone were unsuccessful.
Natanz is home to a fuel enrichment plant and a pilot fuel enrichment plant, the International Atomic Energy Agency said in a report on Iran's nuclear program published last week.
North Korea -- which conducted two nuclear tests in 2006 and 2009 -- revealed a year ago that it is running a uranium enrichment facility. Highly enriched uranium can be used to make weapons, providing Pyongyang with a second way of building nuclear bombs in addition to its existing plutonium program.
Both North Korea and Iran are under United Nations sanctions for their nuclear programs. The North has expressed interest in rejoining international disarmament talks it walked away from in 2009.
The source's information came days after the U.N. nuclear watchdog expressed "serious concerns" on possible military dimensions to Iran's nuclear program.
The IAEA said in its report that it believes the country "has carried out activities relevant to the development of a nuclear explosive device" under a "structured program" until 2003, and "some activities may still be ongoing."
The source with access to intelligence on the years-long weapons collaboration between Pyongyang and Tehran said the North Koreans are visiting Iran via third countries and many of them are being rotated in every three to six months.
The North Korean experts are from the country's so-called Room 99, which is directly supervised by the North's ruling Workers' Party Munitions Industry Department. The room, which can be translated as office or bureau, is widely believed to be engaged in exports of weapons and military technology.
South Korea's top spy agency, the National Intelligence Service, said it could not confirm the North Korean-Iranian cooperation, citing intelligence matters.
A senior South Korean official said Seoul is keeping a close eye on developments.
"It's not a matter that the government can officially confirm," another government official said. That official added that nuclear cooperation between North Korea and Iran has not been confirmed, though the countries have cooperated on missiles. The two officials asked not to be identified, citing office policy.
The Associated Press reported late last year that Mohammad Reza Heydari, a former Iranian diplomat in charge of airports who defected to the West earlier in 2010, said he saw many North Korean technicians repeatedly and discreetly travel to Iran between 2002 and 2007 to work on the country's nuclear program.
AP also reported that Saed Jalili, Iran's chief nuclear negotiator, denied North Korean technicians visited his country to assist with nuclear weapons development, calling the defector's claim "totally fabricated."
Arms exports have been one of the major sources of hard currency for the cash-strapped communist country.
North Korea and Iran have been suspected of exchanging missile parts and technology, especially during the 1980-1988 Iran-Iraq war.
In 2006, Iran's military commander publicly acknowledged that his country had obtained Scud-B and Scud-C missiles from North Korea during the war, but no longer needs Pyongyang's assistance.
North Korean leader Kim Jong-il said in his book published in 2005 that his country's missile doctrine is peaceful in nature and poses no threat. (Yonhap)
북한에서 핵과 미사일 개발에 참여하고 있는 핵심 기술인력 수백 여명이 이란의 주요 핵ㆍ미사일 관련 시설에서 근무 중인 것으로 알려졌다.
이는 북한이 이란의 핵ㆍ미사일 '커넥션' 의혹을 입증해주는 것으로 이란 핵-북한 핵 사태의 전개와 국제사회의 대응에 상당한 파장이 예상되고 있다.
북한 핵문제에 정통한 외교소식통은 13일 "이란 내 10여 곳의 핵과 미사일 시설에서 수백 명의 북한 엔지니어와 과학자들이 일하고 있는 것으로 휴민트(인적정보)를 통해 확인됐다"면서 "이는 수년째 지속돼온 것"이라고 말했다.
이들 기술인력은 노동당 군수공업부 소속의 '99호실' 출신들로 3개월 또는 6개월 단위로 교대근무를 하고 있는 것으로 알려졌다.
이들은 제3국을 경유해 이란에 입국하고 있으며 나타즈와 쿰 등 이란 내 10여개 핵ㆍ미사일 관련 시설에 분산 배치돼 북한의 핵과 미사일 개발을 지원하고 있는 것으로 전해졌다.
정부 고위당국자는 사실 확인을 하지 않은 채 "관련 동향을 예의주시하고 있다"고 밝혔다.
또 다른 복수의 정부 당국자는 "정부로서는 공식 확인해줄 수 없는 사항"이라면서 "북한과 이란의 미사일 협력은 일정부분 확인되고 있으나 핵 협력은 아직 확인된 바 없다"고 말했다.
국가정보원 측은 "정보사항이어서 확인해줄 수 없다"고 답했다.
국제원자력기구(IAEA)는 최근 발표한 이란 핵 관련 보고서에서 북한과의 핵개발 협력 부분은 적시하지 않았다.
그러나 미국 워싱턴포스트(WP)는 지난 7일 "이란이 옛 소련ㆍ북한 등 외국 과학자들의 도움을 받아 핵무기 개발에 필요한 핵심 기술들을 이미 확보한 것으로 IAEA가 결론을 내렸다"고 보도했다.
북한과 이란은 지난 1980년대부터 미사일을 중심으로 군사협력과 기술제휴를 해왔으며 북한의 대포동 2호 미사일과 이란의 샤하브-5가 이 같은 협력의 산물인 것으로 알려졌다.