Akbari was hanged, the BBC reported, citing Iranian state media.

Earlier, Iran's Supreme Court rejected his appeal, upholding the original death sentence.

The former official was arrested in 2019 and accused of spying for the British intelligence agency MI6, for which he allegedly received more than two million dollars in various currencies.

In an audio recording obtained by the BBC's Persian Service, Akbari said he confessed to crimes he did not commit after being tortured.

British Prime Minister Rishi Sunak called Akbar's execution "a heartless and cowardly act by a barbaric regime."

Earlier on Friday, the country's foreign minister, James Cleverley, called for Akbara's immediate release and called the death sentence politically motivated.

In response to Akbar's execution, London imposed sanctions on Iran's Attorney General, Mohammad Jafar Montazeri.

The French authorities also condemned the execution, in connection with this the Iranian ambassador in Paris was summoned to the Ministry of Foreign Affairs.

The Ministry of Foreign Affairs of Iran, in turn, summoned the British ambassador in connection with "London's interference in the sphere of national security of Iran."

Akbari held the post of Deputy Minister of Defense under President Mohammad Khatami, who led the country in 1997-2005.