Israel recently carried out practice detonations containing nuclear material, in an effort to examine the effects of a potential "dirty bomb" attack against it, Haaretz daily newspaper reported this week.
Over 20 detonations were carried out in the practice, which contained between a half pound and 55 pounds of explosives. The practice was conducted at a closed facility in the southern Negev Desert.
"The research concluded that high-level radiation was measured at the center of the explosions, with a low level of dispersal of radiation by particles carried by the wind. Sources at the reactor said this doesn't pose a substantial danger beyond the psychological effect," Haaretz reported.
It is likely Israel leaked the results of the test, given they concluded that such devices posed little threat to the country.
"Dirty bombs" are regular explosives detonated with nuclear material nearby. They are intended to contaminate a wide area with radiation.
Israeli defense officials refused to comment on the report.
Israel has never publicly declared what its extensive nuclear weapons program. It is the only country in the world to possess such weapons without declaring them and is also the only country in the middle east to possess them.
In addition to the explosive experiments, another test called "Red House" was conducted, in which Israel tested the results of undetonated radioactive material left in a crowded area.
It is estimated that Israel has over 200 nuclear missiles.
Environmental group Greenpeace found in a report that Israel is conducting nuclear exercises in the Nahal Sorek, Negev, Eilabun, Haifa, Yodfat, Tiros and Kefer Zekeriya regions.
Its possible the leaked test results were also a cover for nuclear weapons testing, though the intense secrecy makes verification next to impossible.