http://www.bbc.co.uk/news/world-middle-east-11860928An Iranian nuclear scientist has been killed and another wounded in two separate but similar attacks, according to Iranian media reports.
The scientists were targeted in Tehran by attackers who attached bombs to each of their cars, reports said.
The scientist killed has been named as Majid Shahriari of Shahid Beheshti University in Tehran, according to the official Irna news agency.
Another scientist was killed in a bomb blast at the beginning of the year.
The state television website says attackers riding on motorcycles attached bombs to the car windows of the scientists as they were driving to their workplaces on Monday morning.
"In a criminal terrorist act, the agents of the Zionist regime attacked two prominent university professors who were on their way to work," Iran's state television's website reported.
http://news.bbc.co.uk/2/hi/middle_east/8456076.stmAnd a reporter for a government-owned newspaper told the BBC the scientist's death was likely to be a setback for the Iranian nuclear programme - another strange comment in a country where defiance is usually the rule.
But scientists in Britain and the United States pointed out that, from his substantial body of published research,[b] Dr Mohammadi was most unlikely to have been working on Iran's nuclear programme.]/b]
Meanwhile, the Iranian opposition highlighted his name on a list of 240 academics who had pledged their support to the leading opposition candidate, Mir-Hossein Mousavi, in the disputed presidential elections.
This is not the sort of action calculated to bring such a fulsome tribute from the government as it battles Mr Mousavi's supporters.
So this all leaves more questions than answers.
Deep suspicions
One possibility is that Iran's opponents simply attacked the wrong target, mistakenly believing they could harm the nuclear programme.
Yet it was the official media that named him as a nuclear scientist.
The opposition will suspect it was a government attack, designed to kill one of their supporters and intimidate others.
Certainly the suggestion foreign agents penetrated into the heart of Tehran, with the current intense security, raises deep suspicions.
Cracking down
But why the Iranian government would target Dr Mohammadi in particular is another unanswered question.
If he was an opponent of the government, he was certainly not a leading one.
Whatever the precise circumstances of his death, the opposition will fear this will be another reason for cracking down on their activities.
If that is the case, expect more arrests and government warnings in the coming days.
Nuclear controversy
And the killing will do little to help the already faltering dialogue between Iran and the West over the nuclear programme.
Representatives of six major world powers meet in New York on Saturday to discuss the current impasse in the nuclear talks.
The West will be pressing speedy adoption of a new set of sanctions.
One thing all those round the table should be able to agree is that Iran is becoming an increasingly complicated country to understand and to negotiate with, as the domestic political situation and the nuclear controversy become ever more closely intertwined.
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