Australia resettled two Rwandan men accused of murdering eight tourists, as part of a secret agreement reached between the Obama administration and Turnbull government in 2016, Politico has reported .

The report said the men confessed to their involvement in a grisly 1999 attack on a group of vacationers where eight foreigners — including two US citizens — were bludgeoned to death.

The men were brought to the US for trial, but the case against them was dropped, Politico wrote.

They were recently bargained off as part of a migrant swap between the US and Australia, and have since been quietly resettled in Australia under humanitarian protection.

The story made waves in Australia as it prepares for a federal election on Saturday.

Two men accused of butchering foreigners were resettled in Australian society under humanitarian protection as part of a secret swap deal between the US and Australia, according to a report published by Politico on Wednesday.

The story has made waves in Australia as it prepares for its federal election on Saturday. Prime Minister Scott Morrison, who is seeking re-election, has been eager to paint his coalition government as tough on immigration, though news of the men's resettlement may muddle that image.

The two men, Leonidas Bimenyimana and Gregoire Nyaminani, as well as a third man who remains in an ICE detention center near Miami, confessed to their involvement in a grisly 1999 attack on a group of vacationers participating in a gorilla-watching trip in Uganda, Politico said.

In the attack, a large group of Rwandan rebels descended onto Bwindi Impenetrable National Park and bludgeoned eight tourists to death, including citizens from Britain, America, New Zealand, and Uganda. Several other foreigners were taken hostage in the exchange.

The three men, who identified as members of the Hutu rebel group, were flown to US soil in 2003 for trial over the killing of two US citizens. They were charged under terrorism statutes, Politico said, but eventually the case was dropped after a US judge ruled that the men had been tortured in Rwanda and confessed to the crimes under duress.

The men were jailed at US detention centers, and claimed they could not return to Rwanda as they faced persecution on ethnic grounds. Without US citizenship, the men were left waiting in detention as their circumstances were reassessed, the report said.

Bimenyimana and Nyaminani are said to have been swapped as part of an alleged "one-off deal" struck between the Obama administration and then-Australian Prime Minister Malcolm Turnbull in 2016. Under the secretive agreement, the US said it would take in up to 1,250 migrants held by Australia in offshore detention centers Manus Island and Nauru, in exchange for Australia taking Central American refugees that the US was eager to deport.

Read more: Everything we know about what Trump called the 'worst deal ever' between the US and Australia

At the time of these discussions, Australia was desperately seeking a solution to its controversial policy of sending asylum seekers that arrived by sea to offshore sites, a policy that eventually reached crisis and garnered international scrutiny.

"Please, if we can agree to stick to the deal, you have complete discretion in terms of a security assessment," Turnbull told Trump during a heated phone discussion leaked to the Washington Post in August 2017. "Basically, we are taking people from the previous administration that they were very keen on getting out of the United States. We will take more. We will take anyone that you want us to take."

According to the transcript, Trump responded by saying the deal was "rotten," and said the deal made him look like a "dope." The official details of the exchange have mostly been kept under wraps.

News of the resettlement is a bad look for Australia's tough immigration policies

Protesters from the Refugee Action Coalition hold placards during a demonstration outside the offices of the Australian Government Department of Immigration and Border Protection in Sydney, Australia, April 29, 2016. Reuters/David Gray

According to Politico, the two men are said to have been resettled late last year, around the time when Australia was locked in heated debate over proposed legislation to bring sick detainees on Manus Island and Nauru to Australia for medical treatment. In February, Prime Minister Morrison said passing the bill would pave the way for 'rapists and pedophiles' to enter the country. Legislation eventually passed in February, though as of April only one person is thought to have been transferred to Australia for treatment under the law.

Morrison has since responded to questions about the alleged migrant swap and did not explicitly deny the Politico report.

"Every single person that comes to Australia under any such arrangements are the subjects of both character and security assessments," he said on Thursday during a press conference in Canberra.

"I don't intend to make a commentary on allegations that have been made in open source information, but simply to assure Australians that they are the processes that we undertake and these are the same security agencies that have thwarted 15 terrorist attacks."