Seen here during his trial, an Iranian man convicted of killing a scientist has been hanged.

State news reported that Majid Jamali Fashi was executed Tuesday.

Accused of being an Israeli Mossad agent, the 24-year-old was sentenced to death last August for killing Massoud Ali-Mohammadi.

The Tehran University professor was killed in 2010 by a remote-controlled motorcycle bomb outside his home.

Iranian authorities said Fashi confessed to the crime.

A spokesman for Iran's Atomic Energy Organisation said at the time that Ali-Mohammadi was not involved in its activities.

Tehran has accused Israel and the United States of assassinating four Iranian scientists since 2010 -- most recently in January, when the deputy director of a uranium enrichment facility was killed by a car bomb.

Israel refuses to officially comment, but an unnamed source previously said the assassinations have panicked the scientists' surviving colleagues.

Israel has openly threatened military action against Iran over its nuclear programme.

Lindsey Parietti, Reuters