A former CIA officer who allegedly shared secrets with a New York Times reporter about the US effort to disrupt the Iranian nuclear programme has been convicted on espionage charges.

Jeffrey Sterling on Monday was found guilty on nine counts for disclosing classified information in a US court in Alexandria, Virginia in a case seen as a prime example of the Obama administrations efforts to go after whistleblowers.

The case had drawn particular attention because it raised questions about journalists' right to protect their sources as the US justice department sought to force Times reporter James Risen to testify. He had vowed to go to jail rather than reveal his source and the government ultimately decided not to force him to testify.

Sterling allegedly shared information with Risen about a CIA plot to secretly give Iran false information meant to derail its nuclear programme. The government claimed the publication had endangered agents and ended the effort.

The information appeared in Risen's book State of War and prosecutors argued that only Sterling could have provided the information about the mission, which former national security adviser Condoleezza Rice testified was among the government's most closely held secrets during her tenure as well as one of its best chances to derail Iran's nuclear-weapons ambitions.

Prosecutors had acknowledged a lack of direct evidence against Sterling but said the circumstantial evidence against him was overwhelming. Defense lawyers had said the evidence showed that Capitol Hill staffers who had been briefed on the classified operation were more likely the source of the leak.

Following the verdict, defense lawyer Edward MacMahon said he is disappointed in the verdict but "we still believe in Jeffrey's innocence". He said the defense will pursue every available legal option to get the jury's verdict overturned.

Sterling will have the option to appeal his case after he is sentenced in April. Motions to dismiss the case on various legal grounds are also still pending.

The classified operation at the heart of the trial involved using a CIA asset nicknamed Merlin, who had been a Russian nuclear engineer, to foist deliberately flawed nuclear-weapons blueprints on the Iranians, hoping they would spend years trying to develop parts that had no hope of ever working.