TEHRAN Iran admitted Monday that its controversial uranium enrichment centrifuges had been affected by a malicious computer virus, as reported by Western diplomats last week.
Hours earlier, car bombs killed a top Iranian nuclear scientist in Tehran and wounded another.
Both events may color a resumption of talks on nuclear issues next week with the five permanent members of the U.N. Security Council and Germany.
President Mahmoud Ahmadinejad told a news conference Iran would attend the talks on December 5, but restated its position that its uranium enrichment program, which it says is purely for power generation, was not negotiable.
Major Western powers as well as Israel and Russia have become increasingly concerned that Iran's program may soon give it the capacity to build and launch a nuclear bomb, despite four rounds of U.N. sanctions.
Israel and the United States have not ruled out pre-emptive military strikes. But the emergence of Stuxnet, which some experts believe was aimed specifically at Iran's nuclear installations, shows Tehran's foes may no longer be restricted to conventional diplomatic and military options.
Ahmadinejad did not specify whether he was referring to the Stuxnet virus identified by Western security experts, but said:
"They succeeded in creating problems for a limited number of our centrifuges with the software they had installed in electronic parts. But the problem has been resolved."
International talks on Iran's nuclear program have made little or no progress and been stalled for more than a year.
Russia's RIA news agency quoted Iran's ambassador to Moscow as saying the latest round would be held in Geneva.
Ahmadinejad said Iran was ready to discuss nuclear cooperation and international problems, but not enrichment.
"The complete enrichment cycle and the production of fuel are basic rights of (IAEA) member states and are non-negotiable," Ahmadinejad said.
A senior Western diplomat in Tehran whose country is involved in the talks said no major breakthrough was expected.
"Iran has always tried to evade pressure by expressing its readiness for talks. But we want to discuss sensitive issues like enrichment," the diplomat told Reuters on condition of anonymity.
Pressure has been increasing on Iran since the discovery last year of a hitherto undeclared underground enrichment site under construction near Qom.
In the past few months it has arrested a number of alleged nuclear spies, warning citizens against leaking information to foreign secret services.
Iran's top nuclear official, Ali Akbar Salehi, said the scientist killed in Tehran Monday, Majid Shahriyari, had had a role in Iran's biggest nuclear projects, but gave no further details.
The scientist injured by a separate bomb in Tehran, Fereydoun Abbasi-Davani, is personally subject to U.N. sanctions because of alleged involvement in nuclear weapons research.
The state news agency IRNA said motorcyclists had approached both scientists as they drove to work and attached bombs to the outside of their cars before riding off. Both men's wives were injured.
Another nuclear scientist, Massoud Ali-Mohammadi, was killed in Tehran by a remote-controlled bomb in January. Western security sources said at the time that he had worked closely with Abbasi-Davani.
Ahmadinejad blamed the attacks on Iran's enemy Israel and its Western allies.
He also dismissed as "mischief" news reports based on secret U.S. diplomatic cables published by WikiLeaks indicating that many of Iran's Arab neighbors had pressed for a U.S. strike against its nuclear program.
"Regional countries are all friends with each other. Such mischief will have no impact on the relations of countries," he said.
"Some part of the American government produced these documents. We don't think this information was leaked. We think it was organized to be released on a regular basis, and they are pursuing political goals."
(Additional reporting by Ramin Mostafavi and Mitra Amiri in Tehran and Fredrik Dahl in Vienna; Writing by Robin Pomeroy and Parisa Hafezi; Editing by Kevin Liffey)