"The agency has serious concerns regarding possible military dimensions to Iran's nuclear program," CNN quoted the report as saying. "After assessing carefully and critically the extensive information available to it, the agency finds the information to be, overall, credible. The information indicates that Iran has carried out activities relevant to the development of a nuclear explosive device."

According to the IAEA report, Iran continued nuclear weapons research and technology development after 2003, at a time when it declared a halt in its nuclear program. The report said that Iran had temporarily frozen nuclear activities, but that there was evidence the program continued to be carried out at a more modest pace.

Iranian officials slammed the report as a distortion of facts aimed at satisfying U.S. political interests.

President Mahmoud Ahmadinejad called Yukiya Amano, the IAEA’s head, a U.S. puppet, saying that "they [the U.S. officials] have appointed a man as the chief of the IAEA who has no authority."

UN nuclear watchdog’s new report has triggered a new wave of threats from Israel since the senior members of the Israeli government backed the possibility of launching strikes against Iran’s nuclear facilities.

Israeli President Shimon Peres reiterated Sunday that an attack on Iran is becoming increasingly likely.

Iranian Defense Minister Brig. Gen. Ahmad Vahidi said Iranian armed forces were in "full combat readiness and will give a crushing response to those daring to attack the country," Irna reported.

Earlier on Tuesday, the Russian Foreign Ministry expressed dismay that the IAEA report has become a source of increased tension surrounding Iran's nuclear program.

It also questioned whether the IAEA was able ensure the appropriate confidentiality for its work, adding that the IAEA should be guided by the principle: "Do no harm."