Friends of Australian economist Sean Turnell have expressed concerns after a bomb attack at the Myanmar prison where he is being held.
French news wire Agence France-Presse, citing an anonymous source familiar with the case, reported earlier this week that the Macquarie University academic had been relocated to Insein prison in Myanmar's biggest city, Yangon.
Last month Professor Turnell was sentenced to three years in prison in a closed-door military court for alleged breaches of the Official Secrets Act, a conviction the Australian government rejected.
Amnesty International in Australia also confirmed to the ABC that Professor Turnell was being held in Insein, as did another source familiar with the matter.
A spokesperson at the Department of Foreign Affairs and Trade said they could not comment on Professor Turnell's whereabouts due to privacy obligations.
"The Department of Foreign Affairs and Trade is providing consular assistance to Professor Turnell and his family and will continue to do so for as long as required," they said in a statement.
"The government is not aware of any Australians who were impacted by the blasts and gunfire in the vicinity of Insein Prison in Yangon."
The sprawling colonial-era complex has a reputation for detaining political prisoners, as well as foreign nationals, including former British ambassador to Myanmar Vicky Bowman and Japanese journalist Toru Kubota.
Professor Turnell was also previously held at Insein prison for a period last year, before being moved to a special court for trial in the capital.
Tim Harcourt, a friend of Professor Turnell, said reports of violence in the vicinity were worrying for his family and friends.
"The case [for bringing him home] is already strong, but now you could say you've got him in harm's way as well," Professor Harcourt said.
"But at the end of the day, he shouldn't have been tried and he shouldn't have been arrested.
"If anything happens, I'll hold the Myanmar junta responsible.
"Their sentencing and the opaque legal system is bad enough as it is, but then to put him in harm's way ... This will be on their heads, if anything happens."
Little-known group claims responsibility for attack
The country has been in turmoil since the junta overthrew the democratically-elected government of de facto leader Aung San Suu Kyi on February 1 last year.
Professor Turnell, an economic advisor to Ms Suu Kyi, was detained in the days after.
More than 2,370 people have been killed by the junta since the February coup, according to the Assistance Association for Political Prisoners, and more than 15,000 have been arrested.
State-owned MRTV said the explosions were caused by "mines inside parcels" that killed three prison officers and five visitors, inlcuding a 10-year-old girl, and wounded 18 people.
A wounded witness said gunfire also broke out after the bombs exploded at the parcel counter.
According to reports, one of those killed was the mother of a prominent activist known as Ko James. She had gone to the prison to deliver food to her son.
Amnesty International said it was "extremely disturbed" by reports of the explosions.
"We express condolences to the victims," the human rights group said in a tweet.
"No one should die delivering parcels to their loved ones."
An Amnesty spokesperson said that thousands have been arbitrarily detained since the coup last year.
"The violence at Insein prison is infuriating and heartbreaking because it shows how those detained and their visiting families are both at risk of serious harm," an Amnesty spokesperson said.
"We repeat our call for Myanmar's military authorities to immediately release all those arrested for peacefully exercising their human rights. The incident must also be independently investigated."
Several resistance groups engaged in struggle against the military, including the Yangon Revolution Force, Yangon Urban Guerrillas and the General Strike Committee, quickly released statements condemning the attacks for hurting civilians.
However, a little-known anti-junta group later posted a statement on Telegram saying it had carried out the attack.
The Special Task Agency of Burma said it launched the mission because of continued oppression of revolutionary fighters by prison personnel.
It said the civilian casualties were caused by indiscriminate gunfire by security forces after the blasts.
Claims of responsibility, especially in cases where civilians are killed, are often controversial because while many anti-junta groups operate autonomously and with little discipline or training, there is suspicion that some attacks are carried out by provocateurs working for the government to discredit the resistance movement.
ABC/wires