A former CIA officer has been convicted of leaking classified details of a US operation against Iran to a reporter, BBC News said.

Jeffrey Sterling denied the leak but was found guilty in a Virginia court of all nine counts he faced.

New York Times reporter James Risen was the recipient of what former Secretary of State Condoleezza Rice testified was one of the most closely held secrets.

But he was not called to give evidence because he said he would never reveal his sources, even if jailed.

The US operation to thwart Iran's nuclear plans involved using a CIA agent nicknamed Merlin to pass on erroneous nuclear blueprints to Iran.

Mr Risen's book State of War described this plan as botched and counter-productive because they could have armed Iran with nuclear expertise.

Defence lawyers admitted the journalist and former agent had a relationship, laid bare in phone calls and emails, but they argued there was no evidence the two men discussed anything classified.

Sterling will be sentenced in April.