CANBERRA, Australia (AP) — A dozen celebrated Australians on Thursday sent an open letter to their government warning that asylum seekers could die at a decommissioned immigration camp on Papua New Guinea where food, water power and medical care were cut off more than three weeks ago.

The 12 former Australians of the Year called on Australia to restore basic services to the camp on Manus Island and allow doctors to provide care there as reports emerged of an operation on Thursday to evict the remaining asylum seekers.

"It is inevitable that people will become sick and even die through the lack of basic sanitation, food, water and medical care," the letter to Prime Minister Malcolm Turnbull and opposition leader Bill Shorten said.

An Australian of the Year is chosen annually by a government-appointed board to celebrate the achievements and contributions to society of eminent citizens who are regarded as role models for their nation. The signatories span 32 years from 1983 to 2015.

Their intervention follows several street marches in Australian cities condemning Australia's treatment of asylum seekers on Papua New Guinea.

Australia pays Papua New Guinea, its nearest neighbor, and the tiny Pacific nation of Nauru to hold thousands of asylum seekers from Africa, the Middle East and Asia who have attempted to reach Australian shores by boat since mid-2013.

The United States has agreed to resettle up to 1,250 refugees among of them under a deal struck by President Barack Obama's administration that President Donald Trump has reluctantly decided to honor.

The male-only camp inside a Manus Island navy base was declared closed on Oct. 31 based on the Papua New Guinea Supreme Court's ruling last year that Australia's policy of housing asylum seekers there was unconstitutional.

The asylum seekers fear for their safety in the alternative shelters available in the nearby town of Lorengau because of threats from local residents.

Police said of the 606 men in the camp when it officially closed, 379 remained there by Wednesday. Refugee advocates said 420 men remained.

Police had ruled out using force to remove the men.

But Australian Immigration and Border Protection Minister Peter Dutton said a police operation was underway on Manus on Thursday to relocate the remainder.

"It's outrageous that people are still there and they've trashed the facility. They're living in squalor," Dutton told Sydney Radio 2GB.

"But there is an operation involving police at the center this morning. It's like the tenant that won't move out of the house when you've built a new house for them to move into," he added.

Amnesty International cited reports of Papua New Guinea immigration officials armed with sticks and knives entering the Manus camp on Thursday.

"The risks of serious injury if the authorities use force now is completely foreseeable," the London-based rights group's researcher Kate Schuetze said in a statement.

Asylum seekers used social media to report their possessions were being burnt at the camp.

Authorities have previously made conditions tougher in the camp by emptying drinking water tanks and removing shelters. Deadlines to abandon the camp have passed without authorities taking action.

Police said in a statement on Wednesday that plans to relocate the men had been deferred because the Papua New Guinea Supreme Court had agreed to hear an application to restore services to the Manus facility on human rights grounds

A judge refused the application on Nov.6, but three judges agreed on Wednesday to hear an appeal next month.

The United Nations Human Rights Committee this month criticized Australia for allowing the Manus camp to close "without adequate arrangements for long-term viable relocation solutions for all refugees and asylum-seekers."

The committee found conditions in the facilities in Papua New Guinea and Nauru included inadequate mental health services, serious safety concerns and instances of assault, sexual abuse, self-harm and suspicious deaths. The harsh conditions compelled some asylum seekers to return to their homelands despite the risks that they face there, it said.