The verdict comes amid tensions between Iran and Britain over the seizure of oil tankers in recent weeks.

Iran has jailed a British dual national convicted of spying for Israel and upheld the sentence of a British Council staffer for "cultural infiltration", the judiciary said on Tuesday.

Anousheh Ashouri, a woman with British and Iranian citizenship, got 10 years in prison for feeding information to Israel's Mossad spy agency, judiciary spokesman Gholamhossein Esmaili said.

The latest Iranian national with a Western passport to be detained in the Islamic republic, she was also handed a two-year prison term for receiving 33,000 euros ($36,600) in illicit funds from Israel and ordered to pay the same amount in fines.

Her sentence came as Iran's judiciary confirmed a 10-year jail sentence against British Council staffer Aras Amiri for "cultural infiltration".

Amiri was "sentenced to 10 years in jail... and she is already serving her term. This verdict has been upheld by the court," said Esmaili.

"This person... was identified by us because of her cultural infiltration in society through arts and her widespread activities," the judiciary spokesman added.

The judiciary's Mizan Online website reported Amiri's original sentence on May 13, saying she had "made a straightforward confession".

At the time, Esmaili said she had been tasked with drawing up and managing cultural "infiltration" projects.

Amiri, a Iranian national who had been living in London, was reportedly arrested in 2018 during a trip to visit relatives in Iran.

Iranian authorities shut down the British Council's office in Tehran more than a decade ago for what Esmaili described as "illegal activities".

The council describes itself as the United Kingdom's organisation for cultural relations and educational opportunities.

High seas tensions

The verdicts come amid tensions between Iran and US ally Britain over the seizure of oil tankers in recent weeks.

An Iranian supertanker was seized off the British overseas territory of Gibraltar on July 4 on suspicion of shipping oil to Syria in breach of EU sanctions.

That vessel has been released, but Iran continues to hold a British-flagged tanker it seized in the Gulf on July 19 for breaking "international maritime rules".

Tensions had already heightened over the fate of British-Iranian mother Nazanin Zaghari-Ratcliffe who was arrested by Iranian authorities in 2016 as she was leaving Tehran.

Zaghari-Ratcliffe, who worked for the Thomson Reuters Foundation, was put on trial and is now serving a five-year jail sentence for allegedly trying to topple the Iranian government.

Other Iranian dual nationals jailed in Iran include Iranian-American Siamak Namazi and his father Baquer, who are serving 10-year sentences for espionage in a case that has outraged Washington.

And last month Iran confirmed the arrest of French-Iranian academic Fariba Adelkhah, 60, without giving any details on the case.

In another ruling announced on Tuesday, a second person was jailed after being found guilty of spying for Israel.

Iranian national Ali Johari was sentenced to 10 years for various espionage offences, including "widespread connections with Mossad... and meeting with various elements linked to the Zionists," Esmaili said.

Johari had been in contact with operatives in India, Laos and Sri Lanka, among other countries, and also travelled to "occupied lands", the judiciary added.

He had been in the process of "getting citizenship from this country", said Esmaili, in apparent reference to Israel.

Johari also received two years for accepting illicit funds and was ordered to pay that unspecified amount in fines, said Esmaili.