The US has condemned the killing of an Iranian nuclear scientist in a car bomb attack in north Tehran.

National Security Council spokesman Tommy Vietor said the US "had absolutely nothing to do" with the attack.

Mostafa Ahmadi-Roshan, who worked at the Natanz uranium enrichment facility, died along with the driver of the car.

Several Iranian nuclear scientists have been assassinated in recent years, with Iran blaming Israel and the US.

Both deny any involvement.

[link to www.bbc.co.uk]