Iranian courts have sentenced one person to death for spying for the CIA, jailed two others for 10 years for the same crime, and have imprisoned a fourth person for 10 years for spying for Britain, the judiciary says.

Key points: It is not yet known if any of those sentences include the three Australians currently detained

It is not yet known if any of those sentences include the three Australians currently detained The death sentence ruling has been appealed

The death sentence ruling has been appealed The brother of President Hassan Rouhani was sentenced to five years in prison for corruption

The verdicts come amid spiralling tensions between Tehran and the United States since President Donald Trump last year withdrew from Iran's 2015 nuclear deal with major powers and reimposed sanctions that have crippled Iran's economy in order to force Tehran to renegotiate the pact.

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

"One person has been sentenced to death for spying for America's intelligence service … but the ruling has been appealed," judiciary spokesman Gholamhossein Esmaili was quoted as saying by the judiciary's news website, Mizan.

The other two men, identified as Ali Nefriyeh and Mohammad Ali Babapour, received final 10-year sentences for spying for the CIA, and were ordered to repay $55,000 they had received, he said.

Mohammad Amin-Nasab was sentenced to 10 years in prison for spying for British intelligence, Mr Esmaili said.

On the same day, an Iranian court sentenced the brother of President Hassan Rouhani to five years in prison, a judiciary spokesman was quoted as saying by the semi-official Fars news.

In May, Hossein Fereydoun was sentenced to an unspecified jail term in a corruption case that the President's supporters allege was politically motivated.

Mr Esmaili said Mr Freydoun was jailed for five years but said — without giving details — he may face further charges in another case, Fars reported.

Reuters