Iran's president accused Israel and the West of being behind a pair of daring bomb attacks that killed one nuclear scientist and wounded another in their cars on the streets of Tehran on Monday. He also admitted for the first time that a computer worm had affected centrifuges in Iran's uranium enrichment program.

Mahmoud Ahmadinejad and other Iranian officials vowed that the nuclear program would not be hampered by what they described as a campaign to sabotage it — whether by assassination or by the computer virus.

The United States and its allies say Iran is seeking to build a nuclear bomb, a claim Tehran denies.   

The two bomb attacks occurred when assailants on motorcycles attached magnetized bombs to the cars of two nuclear scientists as they drove to work in separate parts of the capital Monday morning.

They detonated seconds later, killing one scientist, wounding another and wounding each of their wives, who were in the cars, Tehran's police chief said. At least two other Iranian nuclear scientists have been killed in recent years, one of them in an attack similar to Monday's.

The wounded scientist, Fereidoun Abbasi, is on a list of figures suspected of links to secret nuclear activities in a 2007 UN sanctions resolution, which puts a travel ban and asset freeze on those listed. The resolution describes him as a Defence Ministry scientist who works closely with Mohsen Fakhrizadeh, believed to head secret nuclear projects. Iranian media said he was a member of the Revolutionary Guard, Iran's strongest military force.

Majid Shahriar, the scientist killed in the bombing, was involved in a major project with Iran's nuclear agency, said the agency's chief, Vice-President Ali Akbar Salehi, though he did not give specifics.

Computer worm affected nuclear centrifuge

"Undoubtedly, the hand of the Zionist regime and Western governments is involved in the assassination," Ahmadinejad told a news conference. He said the attack would not hamper the nuclear program.

Salehi, who was a former teacher of the slain scientist, wept as he went on state TV later to talk of the killing. "They are mistaken if think they can shake us," he said.

On Sunday, diplomatic correspondence made public by the website WikiLeaks revealed that several Mideast countries have urged the United States to take any steps necessary to halt Iran's nuclear program. Israel was among the states that encouraged consideration of a military option for dealing with Tehran.

Asked about the Iranian accusations, Israeli government spokesman Mark Regev said Israel did not comment on such matters. In Washington, U.S. State Department spokesman P.J. Crowley said, "We decry acts of terrorism, wherever they occur. And beyond that, we do not have any information on what happened."   

Meanwhile, Ahmadinejad also acknowledged for the first time that a computer worm affected centrifuges in Iran's uranium enrichment program, which the United Nations has demanded Tehran halt.   

Iran has previously acknowledged discovering the Stuxnet worm, which experts say is calibrated to destroy centrifuges by causing them to spin out of control, at its nuclear facilities. But Iranian officials — including Salehi — said it was discovered and neutralized before it could cause any damage, and they accused the West of trying to sabotage Iran's program.

Ahmadinejad told reporters, "They managed to create problems for a limited number of our centrifuges through the software … installed on electronic parts. But this [virus] was discovered and the problem was resolved."

He said Iranian experts had learned from the attempt and "this became an experience that stops the path for [sabotage] forever."

Earlier in November, UN inspectors found Iran's enrichment program temporarily shut down, according to a recent report by the UN nuclear watchdog. The length and cause of the shutdown were not known, but speculation fell on Stuxnet.

Iran's enrichment program is of international concern because the process can create both fuel for an electricity-generating reactor and nuclear warhead material. Iran insists it wants to enrich only to run a nuclear reactor network.