CNN  — 

The last of the asylum-seeker children detained by Australia on the remote Pacific island of Nauru will be resettled in the United States, the government says.

In a statement Sunday, Australian Prime Minister Scott Morrison announced the final four children and their families would be moved at an unspecified future date.

“This is an important milestone and I want to thank everyone who’s been involved,” Morrison said in a video posted to social media, defending the policy under which all asylum-seekers arriving by boat are held offshore to deter other seaborne arrivals.

The children will be resettled in the US under a deal struck between former Australia Prime Minister Malcolm Turnbull and former US President Barack Obama. President Donald Trump begrudgingly retained the deal.

Refugees advocates on Monday welcomed the news but warned there were still hundreds of people trapped offshore by Australia’s policies and in need of help.

“The Government must get out of the way and let doctors provide urgent medical treatment for the complex and life-threatening medical conditions suffered by men and women in offshore processing,” Asylum Seeker Resource Center director of advocacy Jana Favero said in a statement.

Australia has faced fierce criticism from around the world for its border protection policies introduced in 2013, under which all asylum-seekers who arrive by boat are sent to Nauru or to a men-only camp on Papua New Guinea’s Manus Island. Even those eventually judged to be legitimate refugees are permanently barred from resettlement in Australia.

There have been reports of self-harm, severe mental illness and even deaths in the centers.

In August, a 12-year-old boy was flown to mainland Australia for immediate medical attention after refusing to eat for at least two weeks.

“Now the children, some of them, they are not eating, they are not drinking, anything, they are just laying on the bed, doing nothing … Childhood shouldn’t be like this,” Doctors Without Borders psychiatrist Natalia Hverta Perez said in a video posted to the organization’s social media in October.

The government announcement followed an intensive #KidsOffNauru campaign by World Vision Australia, launched in late 2018 to evacuate the final 119 children from the island.

World Vision Australia Chief Executive Officer Claire Rogers said there were still more than 1,000 people trapped on Nauru and the Papua New Guinea’s Manus Island.

“People who come to us, seeking our help should not be used in a macabre game of politics that kills people and makes children and adults critically ill,” she said in a statement.