An Iranian academic wanted in the US has been released from a Queensland prison, Australian authorities have confirmed.
Reza Dehbashi Kivi, a 38-year-old cancer researcher, was arrested in September 2018 after US authorities accused him of conspiring to export electronic military devices to Iran.
Attorney-General Christian Porter on Saturday night confirmed he'd decided the Iranian man shouldn't be extradited.
Queensland Corrective Services confirmed the University of Queensland PhD student was no longer in their custody, but gave no further information.
News of the release comes hours after Perth couple Mark Firkin and Jolie King returned home after three months in an Iranian prison.
"We know there are others who remain in detention in Iran, including a fellow Australian, and believe intense media coverage may not be helpful for efforts to bring them home," the couple said, in a statement.
Iranian state media agency IRIB reports Mr Dehbashi Kivi returned to Tehran on Saturday.
Mr Porter said the decision to not extradite the researcher came after considering "all the circumstances of this particular case".
"While it is likely that because of (his) nationality some will speculate regarding this matter, consistent with prior practice I do not intend to comment further on the particular details of this case, particularly when any such response from me may diminish our government's capacity to deal with future matters of this type in Australia's best interests," he said.
Mr Dehbashi Kivi battled extradition to the US, raising concerns he couldn't get a fair trial due to prejudice at trial towards Iranians.
"My client is likely to be viewed as a national of an enemy state," his barrister Pouyan Afshar told a Brisbane court in May.
A barrister acting for Mr Porter on behalf of the US government told the same court the UQ researcher allegedly sought to procure and export parts intended for radar application in the electronic warfare branch of the Iranian government.
"Any person who intended to export those parts was required to obtain a licence."
Meanwhile, Perth couple Mr Firkin and Ms King say they are "extremely happy and relieved" to be reunited with their loved ones after all charges against them in Iran were dropped and they were able to fly home.
"We are extremely happy and relieved to be safely back in Australia with those we love," they said in a statement on Saturday.
"While the past few months have been very difficult, we know it has also been tough for those back home who have been worried for us.
The couple spent almost three months in the notorious Evin prison after they were arrested for flying a drone near a military zone without a licence.
Before their arrest, they had been globetrotting for two years and documenting their travels on Instagram and YouTube.
Foreign Minister Marise Payne said the government continues to seek the return of a third Australian, Melbourne University lecturer Kylie Moore-Gilbert, who has been in detention since October 2018.
She described Dr Moore-Gilbert's situation as "very complex".
Australian Kylie Moore-Gilbert remains behind bars in Iran. Source: Supplied
"She has been detained for some considerable time, and has faced the Iranian legal system and has been convicted and sentenced," the Senator said.
"We are continuing our discussions with the Iranian government, we don't accept the charges upon which she was convicted and we will seek to have her returned to Australia."
Drone use with a permit is allowed in Iran, but there are strict conditions, such as not flying drones over people or large crowds, the city of Tehran, or sensitive areas.
Senator Payne reiterated that Australia's official travel advice for Iran is currently set to "reconsider your need to travel", with the highest warning level "do not travel" applying in some parts of the country.
