The report identified the convicted killer as Nasser-Morad Qolipour and said he killed a police officer two months ago.

The hanging brought to at least 155 the number of executions carried out in the Islamic republic so far this year, most of them by hanging and often in public.

At least 177 people were executed in 2006, according to Amnesty International, making Iran the most prolific applier of the death penalty in the world after China.

Capital offences in Iran include murder, rape, armed robbery, apostasy, blasphemy, serious drug trafficking, pederastry, adultery or prostitution, treason and espionage.

Iran has stepped up executions of rapists, drug traffickers and others deemed a public menace in recent months as part of a campaign which it says is aimed at improving security in society.

Last week two murderers were hanged in Tehran in the first public hangings in the Iranian capital for five years, and seven people convicted of rape and kidnapping were hanged in public in the holy city of Mashhad.