An Iranian nuclear scientist was killed when bikers stuck a bomb to his car window as he drove to work yesterday.

A similar attack was carried out at the same time on a second expert in another vehicle but he survived the blast with serious injuries.

Iran's President Mahmoud Ahmadinejad immediately blamed the murder on foreign spies.

He said: "One can undoubtedly see the hands of Israel and Western governments in the assassination."

And head of nuclear operations Ali Akbar Salehi warned the West: "Don't play with fire. The patience of the Iranian nation has limits.

"If it runs out of patience, bad consequences await enemies."

The two scientists were targeted separately by men on motorbikes in Tehran yesterday morning.

Officials named the dead expert as Majid Shahriari, who was in the nuclear engineering department at Shahid Beheshti University.

The injured man was named as Fereydoon Abbasi, who is a specialist in uranium fuel manufacture for power stations. His wife was also hurt in the blast.

Another Iranian scientist, Masoud Ali Mohammadi, was killed by a bomber in January.

There has been worldwide fear over the country's nuclear activity. Tehran says it is for energy but the US suspects it is for weapons.