Canberra (Reuters) - Hundreds of asylum-seekers held in Australian-run detention centers in the Pacific are likely to remain there indefinitely as no other country is willing to resettle them, Minister for Home Affairs Peter Dutton said on Monday.

Australia’s hardline immigration policy requires asylum seekers intercepted at sea trying to reach Australia to be sent for processing to three camps in Papua New Guinea and one on the South Pacific island of Nauru.

They are told they will never be settled in Australia.

As of March 31, there were 1,305 people in the camps, from various countries including Afghanistan, Pakistan, Sudan and Iran.

“We continue to talk to third countries, but let me tell you, there are very few prospects, if any, on the horizon,” Dutton told reporters in Canberra, referring to the chances of the migrants being accepted by other countries.

About 250 people have left the camps for the United States in recent months under a swap agreement which President Donald Trump described as a “dumb deal”.

Under the agreement 1,250 of the migrants could be resettled in the United States. In exchange, Australia accepted 30 Central American refugees late last year.

But even if the United States accepted the full quota, more than 300 people are likely to remain in the Pacific camps, in two impoverished countries with little ability to effectively integrate them.

But asylum-seeker advocates fear the United States will not accept its full quota as Trump has vowed applicants would have to satisfy “extreme vetting”.

U.S. processing has concentrated on individuals with applications that are seen as easier to verify through background checks and who come from counties with closer ties to the United States.

People from Iran, Libya, Somalia, Sudan, Syria and Yemen - countries included in Trump’s travel ban - have seen their applications lag, migrants say.

The prospect of hundreds of people being left behind has fueled condemnation of Australia’s immigration law.

“There is no possibility of hundreds of refugees and asylum seekers to be resettled in PNG and Nauru,” said Ian Rintoul, a spokesman for the advocacy group, Refugee Action Coalition.

“There are no services, no support, no jobs. They have no future.”

Australia defends its tough law saying it has deterred people from making dangerous sea journeys to try to reach its shores after thousands drowned.