BERLIN - Iran may have tested a nuclear bomb in North Korea in 2010, Hans Rühle, who directed the planning department of the German Defense Ministry from 1982 to 1988, wrote on German daily Die Welt's website on Sunday.

According to his article, many intelligence agencies believe that of the two nuclear tests carried out in North Korea in 2010, at least one detonation was an Iranian atomic weapons device. Some intelligence agencies believe that North Korea used its nuclear weapons expertise to test a weapon of mass destruction on behalf of the Iranians .

Rühle, who is widely respected among defense and security officials, writes that "Iran's military was capable of testing a nuclear warhead in North Korea in 2010. It is therefore not surprising if some intelligence agencies are now of the view that North Korea, in fact, in 2010, conducted at least one nuclear test for Iran."

He continues that "for a number of years intelligence agencies have registered close work between North Korea and Iranian experts in connection with the preparation of nuclear tests. The suspicion up until now has been of an underground nuclear weapons test on Iranian territory."

In connection with the North Korean test of an Iranian nuclear weapon, the former German defense official Rühle noted that it is not atypical for countries to test nuclear devices for foreign countries. He cites a list of examples,including the United States conducting tests for the United Kingdom in the 1990's in the state of Nevada. He added that China tested Pakistan's first nuclear weapons in its territory Lop Nur in 1990.

It is unclear which intelligence agencies Rühle is referring to regarding the possible Iranian test in North Korea. He did not cite the sources for the intelligence data.

He provides evidence from a report in last month's scientific journal Nature. According to the article, the Swedish nuclear physicist Lars-Erik de Geer , who works for the Swedish Defense Research Agency in Stockholm, evaluated data in connection with nuclear tests. According to de Geer's conclusions, North Korea likely conducted two secret nuclear weapons tests in 2010. Rühle wrote that Iran's uranium production between 1998 and 2007 has not been accounted for, suggesting that the material was used in North Korea to test a nuclear device.