A monitoring device disguised as a rock exploded last month when Iranian troops near Fordow nuclear plant disturbed it, the Sunday Times reported, citing Western intelligence sources.

According to the report, Iran's Revolutionary Guard were on patrol last month to check terminals connecting data and telephone links at the underground nuclear enrichment plant, when they saw the rock and tried to move it.

"Iranian experts who examined the scene of the explosion found the remains of a device capable of intercepting data from computers at the plant, where uranium is being enriched in centrifuges," said the report, "It is feared a significant source of intelligence may have been lost for the West."

Iran initially kept news of the explosion secret, the report said, but last week, Fereydoun Abbasi-Davani, the country's vice-president and head of its nuclear energy agency, revealed that explosives had been used to cut power lines from the nearby city of Qom to Fordow on August 17. A day later, he said, IAEA inspectors had asked for an unannounced visit to Fordow.

"Does this visit have any connection to that detonation? Who other than the IAEA inspectors can have access to the complex in such a short time?" Abbasi-Davani said on September 17.

Speaking at the annual member state gathering of the International Atomic Energy Agency that day, Abbassi-Davani said "terrorists and saboteurs might have intruded the agency and might be making decisions covertly," to undermine Iran's nuclear program.

"It should be recalled that power cut-off is one of the ways to break down centrifuge machines," he said, referring to the machines used to enrich uranium, which can have both civilian and military purposes.

Iran accused Germany's Siemens on Saturday of implanting tiny explosives inside equipment the Islamic Republic purchased for its disputed nuclear program, a charge the technology giant denied.

Prominent lawmaker Alaeddin Boroujerdi said Iranian security experts discovered the explosives and removed them before detonation, adding that authorities believe the booby-trapped equipment was sold to derail uranium enrichment efforts.

"The equipment was supposed to explode after being put to work, in order to dismantle all our systems," he said. "But the wisdom of our experts thwarted the enemy conspiracy."

Siemens denied the charge and said its nuclear division has had no business with Iran since the 1979 revolution that led to its current clerical state.

"Siemens rejects the allegations and stresses that we have no business ties to the Iranian nuclear program," spokesman for the Munich-based company Alexander Machowetz said.

