Iranian courts have sentenced an alleged CIA spy to death and jailed a second person for 10 years for purportedly working with UK intelligence agencies.

Two others have been sentenced to a decade in prison for allegedly spying for the US, said the Middle Eastern country’s judiciary, which also confirmed the arrest of a British-Iranian anthropologist.

The announcement of the verdicts came amid spiralling tensions between Tehran and Washington.

The US also reimposed sanctions which have plunged Iran into economic crisis.

Tensions high as Trump approves new Iran sanctions: In pictures Show all 17 1 /17 Tensions high as Trump approves new Iran sanctions: In pictures Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, their surface-to-air missile is seen as it shoots down a US surveillance drone EPA Tensions high as Trump approves new Iran sanctions: In pictures This photo shows US RQ-4A Global Hawk unmanned surveillance drone. A drone of this model was shot down by Iran on Thursday 21 June AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures An oil tanker is on fire after it was subject to a suspected attacked at the Gulf of Oman on June 13. The US has blamed Iran for the attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures US President Trump holds up a signed executive order to increase sanctions on Iran on 24 June AP Tensions high as Trump approves new Iran sanctions: In pictures Iranian President Rouhani stated in a televised address that the White House is "afflicted by mental retardation" following the increase in sanctions on 25 June EPA Tensions high as Trump approves new Iran sanctions: In pictures An Iranian navy boat tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures A screenshot from a video released by the US Department of Defense that the US claims to show Iranian removing an unexploded limpet mine form the hull of the Japan-owned ship that was attacked in the Gulf of Oman on June 13 Getty Tensions high as Trump approves new Iran sanctions: In pictures An item reportedly found on the Japan-owned oil tanker that was attacked on June 13 in the Gulf of Oman AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures A handout photograph from the US Department of Defense shows a composite material that the US claim was left behind on the hull of the Japan-owned oil tanker following the removal of an unexploded limpet mine Getty Tensions high as Trump approves new Iran sanctions: In pictures A view from the cabin of an Iranian navy boat as it tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack EPA Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The picture suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The pictures suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack EPA

It was not immediately clear if any of the cases were linked to Iran’s announcement in July that it had captured 17 spies working for the CIA.

Judiciary spokesman Gholamhossein Esmaili did not give any details about the person sentenced to death.

But he said the suspect had appealed and a final decision on their sentence would be made by the appeals court.

Mohammad Amin-Nasab has been jailed for 10 years for aiding British intelligence services. Ali Nefriyeh and Mohammad Ali Babapour were each sentenced to the same prison term for allegedly spying for the CIA.

Mr Esmaili also acknowledged for the first time that authorities had detained British-Iranian academic Kameel Ahmady.

The anthropologist’s wife Shafagh Rahmani said in August that he had been arrested at their home in Tehran and was being held on unknown charges.

Mr Ahmady – who has been a UK citizen for 25 years - is an internationally renowned expert on female circumcision and has written about issues often controversial in Iran, such as women’s rights and child marriage.

Iran said he had been detained over suspected links to institutes affiliated with foreign intelligence services and the case was in its initial investigation phase.

He is the latest of several dual British national to be incarcerated over spying accusations in Iran.

Nazanin Zaghari-Ratcliffe, who is thought to be being held in the same prison as Mr Ahmady, was jailed for five years in April 2016. She has repeatedly gone on hunger strike as she campaigns for release.

British-Australian Kylie Moore-Gilbert, a Cambridge-educated academic who now lectures in Islamic Studies at Melbourne University, was jailed for 10 years earlier this year. She had published work on the 2011 Arab uprisings and authoritarian governments and was reportedly visiting Iran for a conference at a university.

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Aras Amiri, an Iranian citizen who works for the British Council, was also jailed for a decade in August.

Iran, which does not recognise dual nationalities, often hands down heavy sentences on similar charges. Hardliners in Iran view the country as fighting a cultural "soft war" against westernisation, which they believe is attempting to transform the country’s Islamic beliefs.

The UK Foreign Office has yet to comment on the judiciary’s announcements.

Mr Esmaili said an appeals court had also reduced the prison sentence of Hossein Fereidoun, brother of president Hassan Rouhani, from seven years to five years. He was sentenced in May for bribery.

Mr Fereidoun, a close confidante of the president, was accused of financial misconduct dating back to 2016 in charges brought by hardliners who dominate the country's judiciary.