An Iranian university professor has been killed in a bomb attack in the capital Tehran, Iranian media say.
They say that Masoud Mohammadi, a professor of nuclear physics, died after a remotely controlled bomb exploded near his home.
Iranian media describe him as a "devoted revolutionary professor" killed by "anti-revolutionary" groups.
It comes at a time of heightened tension in Iran, following June's disputed presidential election.
Prof Mohammadi of Tehran University "was killed in a booby-trapped motorbike blast" in the city's Qeytariyeh district, Press TV said.
It showed pictures from the scene of the blast, saying windows in the nearby buildings were shattered by the force of the explosion.
Police sealed off the area and launched an investigation into the incident.
No-one has claimed responsibility for the blast.