Australia mum on possible swap of detainees with Iran

Australia's attorney general on Sunday refused to comment whether a prisoner swap was behind the release of two Australians from Iran in exchange for an Iranian student who was facing extradition to the United States.

The blogging couple, Jolie King and Mark Firkin, returned to Australia on Saturday after all charges against them were dropped. They spent almost three months in Tehran's notorious Evin prison after they were arrested for flying a drone near a military zone without a license.

At the same time, Iran's state TV reported that an Iranian scientist, Reza Dehbashi, who was detained for 13 months in Australia for purchasing a defense system for his country from the United States, had returned home.

Dehbashi had been a research student at the University of Queensland.

Attorney General Christian Porter confirmed that Dehbashi would not be extradited to the United States but refused to comment on an apparent swap.

"The Australian government does not comment on the details behind its consideration of particular cases," he said in a statement.

"And while it is likely that because of Mr Dehbashi Kivi's 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.

The US Embassy in Australia did not immediately respond to a request for comment on Sunday.

Donald Rothwell, an Australian National University expert on international law, said the nature of the releases had the hallmarks of a quid pro quo. "It is the inevitable conclusion when one looks at the facts," he told The Associated Press.

"Normally in prisoner swap matters, the details are held very closely by the relevant governments until such time the prisoners have been swapped and handed over to the relevant authorities and returned to their homeland. That's designed so that nothing untoward happens during the process. That is consistent with what we've seen here," he said.

He said although such swaps were common during the Cold War, "this is very exceptional in terms of Australia's practices."