CANBERRA, Australia - U.S. security officers have yet to be authorized by U.S. President Donald Trump's administration to vet refugees held on Pacific islands for potential resettlement in the United States, an Australian official said on Monday.

Trump has reluctantly agreed to honour an Obama administration deal to accept up to 1,250 refugees refused entry into Australia, but has said they will be subjected to "extreme vetting." Australia pays Nauru and Papua New Guinea to keep more than 2,000 asylum seekers - mostly from Iran, Afghanistan and Sri Lanka - in conditions condemned by rights groups.

Mike Pezzullo, secretary of Australia's Department of Immigration and Border Protection, told a Senate committee that U.S. Department of Homeland Security officers were poised to start vetting refugees on the islands as soon as they were authorized.

Pezzullo told the Legal and constitutional Affairs Committee he was confident there would be "movement within the next few, several months."

"The present administration's made it clear they are currently looking at their vetting thresholds," Pezzullo said.

Committee member Senator Nick McKim, who described Trump as "insane," questioned how Pezzulo could have confidence in that time frame, given the White House was "in absolute disarray."

Pezzullo replied that he was relying on advice from Homeland Security and State Department officials.

State Department officials have already conducted preliminary interviews on the islands to ensure that candidates for resettlement were genuine refugees, Pezzullo said.

Trump has described the deal with Australia as "dumb" and raised doubts about whether it will proceed.