A new report in the US has pointed to the recent Melbourne terror attack by Yacqub Khayre in questioning why US President Donald Trump would endorse the Manus Island-Nauru refugee deal with Australia.

The Washington-based Center for Immigration Studies report concluded it was “hard to comprehend” why Mr Trump would move ahead with the deal.

“Especially when he is trying to get a travel ban in place to halt the entry of nationals from some of the very countries Australia’s unwanted refugees come from,” Nayla Rush, CIS senior researcher, wrote.

“And at a time when terrorism is raging across the world.

“One of the latest terrorist acts for which the Islamic State claimed responsibility was committed in Melbourne by Yacqub Khayre, an Australian citizen with a long criminal record who came to Australia from Somalia as a child refugee.

“Maybe we’re missing something.”

The CIS describes itself as an independent, non-partisan, non-profit, research organisation, but has its critics.

The Southern Poverty Law Center included the CIS on its annual list of hate groups, something the CIS has protested and described as “blacklist lies”.

The deal for the US to accept refugees held on Papua New Guinea’s Manus Island and Nauru was struck last year between then US President Barack Obama and Australian Prime Minister Malcolm Turnbull.

Mr Trump and Mr Turnbull had a contentious phone call about the deal just eight days into his presidency on January 28.

The president soon after used Twitter to describe it as a “dumb deal”, although quickly agreed to support it as long as refugees accepted by the US passed extreme vetting.

In return, Australia would accept refugees from Central America.

“Could the United States be getting something out of that deal – beyond Australia’s acceptance of the 50 ‘refugees’ from Costa Rica – that is being kept secret from us?” Ms Rush asked.

– AAP