US drones scanning Iran for nukes

The small, pilotless planes have penetrated Iranian airspace from US military facilities in Iraq, prompting an official complaint from the Iranian government via Swiss channels, the report said. Iran and the United States lack diplomatic relations. US intelligence has begun reviewing its assessments of the Islamic Republic regarding its nuclear capabilities.

Iranian civilians began reporting seeing colored flashes and racing lights in the sky in December, sparking speculation of UFOs.

But Iranian air force commanders, many of them trained in the United States, identified the drones, and Iran's National Security Council decided not to engage them, the report said, citing a senior Iranian official.

US officials familiar with the program told the daily the drones use radar, video, still photography and air filters to scan for evidence of nuclear activity not accessible to satellites.

"The aerial espionage is standard in military preparations for an eventual air attack and is also employed as a tool for intimidation," the Post said.

The drones were deployed along Iran's northern and western borders in April, December and January, the report said. In response Iran's military stepped up defences around its nuclear facilities in southern Isfahan and Bushehr.

But Iran did not take the bait and turn on its radar, which would have revealed vital information about the country's air defence systems, according to the Post.

The US intelligence community, responding to Bush administration concerns about a nuclear-armed Iran, has begun reviewing its assessments of the Islamic Republic, from weapons capabilities to the stability of Tehran's government, US officials said on Saturday.

The broad review includes a new National Intelligence Estimate, or NIE, intended to provide US policy-makers with a comprehensive profile of Iran's economic, political and military strengths, officials said.