(CNN) Nazanin Zaghari-Ratcliffe, the British Iranian mother jailed in Iran three years ago on espionage charges, could be released as part of a prisoner exchange, Iran's Foreign Minister said Wednesday.
Speaking at an Asia Society event in New York, Mohammad Javad Zarif said he had the authority to initiate a wide-ranging exchange, involving prisoners in Iran and those held by the United States or third countries.
In response to a question from the audience, Iran's top diplomat contrasted the case of Zaghari-Ratcliffe, a charity worker who was arrested in April 2016, with the case of an Iranian he said was detained in Australia.
"We have an Iranian woman in Australia who gave birth to a child in prison... on an extradition request by the United States because she was responsible as a translator in a ... purchase operation ... of some transmission equipment for Iranian broadcasting company, that's her charge," the minister said.
"Now we hear about Nazanin Zaghari and her child, and I feel sorry for them, and I've done my best to help, but nobody talks about this lady in Australia," Zarif said.
CNN has reached out to Australian authorities to confirm both the status of the prisoner and the possibility of such a swap.
The UK's Foreign Office told British media Wednesday that UK nationals detained overseas were a priority and their plight was raised "at every level and every opportunity."
Zaghari-Ratcliffe's husband, Richard Ratcliffe, said he was cautiously optimistic about the offer, but maintained a level of skepticism.
"Normally my sense with Iran is nothing is flippant, and so it will have a meaning, but it might not be the obvious meaning," he said, according to the BBC.
Zarif said there were several people detained in the US, or in allied nations, on so-called "phoney" charges. He suggested they be traded for prisoners in Iran whom the US and allies believe are being held on spurious charges.
"So what can I do as a foreign minister? I put this offer on the table, publicly, now. Exchange them. All these people that are in prison -- inside the United States, on extradition request from the United States.
"Let's have an exchange. I"m ready to do it, and I have authority to do it. We've informed the government of the United States six months ago that we are ready. Not a response yet. If they tell you something else, they're lying."
A US State Department official said Wednesday, "the Iranian regime can demonstrate its seriousness regarding consular issues, including Iranians who have been indicted or convicted of criminal violations of US sanctions laws, by releasing innocent US persons immediately."
"We call on Iran to free all unjustly detained and missing US persons, including Xiyue Wang, Robert Levinson, Siamak Namazi, and Nizar Zakka, among others," the official said in a statement.
The official did not address Zarif's claims that he had approached the US about an exchange but had received no response.
Zaghari-Ratcliffe was arrested at Tehran airport three years ago while about to return home to London after visiting family with her daughter Gabriella, who was then 22 months old.
The Iranian government accused her of working with organizations trying to overthrow the regime. She was sentenced to five years in jail and her child was placed in the care of her Iranian parents.
Her employer, the Thomson Reuters Foundation, rejects the allegations. In May last year, Iranian media reported that she was due to face a new trial on "security-related" charges.
Zaghari-Ratcliffe has staged a hunger strike in an attempt to receive medical treatment, and her husband has said that prison guards had asked her to spy on the UK in return for her freedom.
Last month the British government gave her diplomatic protection, meaning it has recognized that her treatment "fails to meet Iran's obligations under international law and elevates it to a formal state to state issue."
Affording diplomatic protection is rare but allows a state to seek protection on behalf of one of its nationals, if it believes it has been wronged by another state.
The Iranian ambassador to the UK tweeted that the move "contravened international law," and insisted that Zaghari-Ratcliffe's Iranian citizenship meant Britain could not give her diplomatic protection.