CANBERRA, Australia - Australia's prime minister said his country's relationship with the United States remained 'very strong' but refused to comment on a newspaper report on Thursday that an angry President Donald Trump cut short their first telephone call as national leaders.

At the heart of the weekend conversation between Trump and Prime Minister Malcolm Turnbull was a deal struck with the Obama administration that would allow mostly Muslim refugees rejected by Australia to be resettled in the United States.

Turnbull declined to comment on reports in The Washington Post that Trump had described the agreement as 'the worst deal ever' and accused Turnbull of seeking to export the 'next Boston bombers.'

The Boston Bombers refer to Tamerlan and Dhozkar Tsarnaev, U.S. citizens born in Kyrgyzstan, who set off two bombs at the 2013 Boston marathon, killing three and injuring more than 260 people.

Turnbull also would not say whether Trump had abruptly ended the expected hour-long conversation after 25 minutes as the Australian attempted to steer the conversation to other topics.

'It's better that these things - these conversations - are conducted candidly, frankly, privately,' Turnbull told reporters.

Turnbull said the strength of the bilateral relation was evident in that Trump agreed to honour the agreement to resettle refugees from among around 1,600 asylum seekers, most of whom are on island camps on the Pacific nations of Nauru and Papua New Guinea. Australia has refused to accept them and instead pays for them to be housed on the impoverished islands.

'I can assure you the relationship is very strong,' Turnbull said. 'The fact we received the assurance that we did, the fact that it was confirmed, the very extensive engagement we have with the new administration underlines the closeness of the alliance. But as Australians know me very well: I stand up for Australia in every forum - public or private.'

Hours after the Washington Post story was published - and after Turnbull's comments - Trump took to Twitter to slam the deal.

'Do you believe it? The Obama Administration agreed to take thousands of illegal immigrants from Australia. Why?' Trump tweeted. 'I will study this dumb deal!'

The Washington Post story shot to the top of trending topics on Twitter in Australia. It was plastered across the top of Australia's major news sites, and the nation's news networks launched running commentaries on it.

Trump, who a day before the conversation had signed an executive order suspending the admission of refugees, had complained that he was 'going to get killed' politically by the deal, the newspaper reported, citing anonymous officials.

'I don't want these people,' Trump reportedly said. Trump also told Turnbull that he had spoken to four world leaders that day and that: 'This is the worst call by far.'

Trump told Turnbull that it was 'my intention' to honour the agreement, a phrase designed to leave the president wriggle room to back out of the deal, the newspaper reported.

There were some mixed-messages from Washington this week on the state of the agreement.

White House spokesman Sean Spicer confirmed on Wednesday that Trump had agreed to honour the deal.

But a White House statement sent to Australian Broadcasting Corp. on Thursday said: 'The president is still considering whether or not he will move forward with this deal at this time.'

The U.S. State Department said in a statement later Thursday that the United States would honour the agreement 'out of respect for close ties to our Australian ally and friend.'

'President Trump's decision to honour the refugee agreement has not changed and Spokesman Spicer's comments stand,' the State Department said.

The ABC spoke to senior Australian government sources who said The Washington Post report was 'substantially accurate.'

Australian officials said the conversation was 'robust' and 'shorter than expected,' while one minister has told the ABC that 'Trump hates this deal.'

Opposition leader Bill Shorten called on Turnbull to be open about his interaction with Trump, saying The Washington Post version of the call was worrying.

'We shouldn't be finding out about what's happening to Australian policy through the news of foreign countries,' Shorten said.

Turnbull has likened himself to Trump in that both are wealthy businessmen who came to politics late in life. Turnbull also has a reputation for blunt conversation and tough negotiations behind closed doors.

Turnbull has resisted pressure this week to join other Western leaders in condemning Trump's temporary ban of immigrants from seven Muslim-majority countries.

'When I have frank advice to give to an American president, I give it privately, as good friends should, as wise prime ministers do when they want to ensure they are best able to protect Australians and Australia's national interest,' Turnbull told reporters on Tuesday.

Some observers suspect Turnbull has held his tongue because he is grateful to Trump for agreeing to honour the refugee deal.