Trump administration to impose new restrictions at border, leaving asylum seekers in limbo

In addition to closing U.S. borders to all but "essential travel" and citing concerns over the spread of the novel coronavrius, the Trump administration announced Friday that unauthorized immigrants accused of crossing illegally will face immediate return to their home countries.

The unprecedented announcement raised major questions about the fate of refugees and asylum seekers who regularly cross the southern border without travel documents.

Administration officials sent a resounding message that detention protocols -- even for those with valid claims to stay in the U.S. -- pose a health risk to immigrants and Border Patrol agents alike.

"Left unchecked, this would cripple our immigration system, overwhelm our healthcare system and severely damage our national security," Trump said on Friday.

The restrictions are set to start Friday night, and last 30 days, according to the Department of Homeland Security. It remains unclear exactly how potential refugees will be handled if they attempt to cross.

"When it comes to asylum, aliens encountered in the field are being assessed on a case by case basis," Customs and Border Protection spokesperson Matthew Dyman said in a statement.

Refugees have maintained long-standing rights under domestic and international law to seek refuge after setting foot in U.S. territory.

The administration already had plans to immediately return asylum seekers, as was first reported earlier this week by the New York Times.

Acting Homeland Security Secretary Chad Wolf said those "without proper travel documentation" will face immediate removal.

"The [Centers for Disease Control and Prevention] Director has determined that the introduction and spread of the coronavirus at the department's Border Patrol stations and detention facilities presents a serious danger to migrants, our frontline agents and officers and the American people," Wolf said.

DHS has screened more than 200,000 people at U.S. ports that were permitted to enter from areas most affected by COVID-19, according to the latest update from the department.

Prior to the announcement, human rights groups and immigrant advocates urged the administration to not impede potential refugees.

"U.S. border officials should continue to allow people to follow the U.S. legal process to request asylum, be properly screened and referred to health facilities if necessary," Amnesty International and Doctors Without Borders, among other advocacy and human rights organizations, said in a joint statement Thursday. "As should be the case for all individuals crossing the southern border,"

Speaking in the White House briefing room on Friday, Secretary of Health and Human Services Alex Azar, said the restrictions would include anyone who would be typically detained in a CBP detention facility, "because of the public health threat."

"We're talking about significant numbers of illegal immigrants," Azar said, while also noting the prospect that agents would be turning around possible refugees.

CBP did not respond to ABC News' questions about specific changes to the asylum process.

It also remains unclear how unaccompanied children will be handled after crossing. Those under 18 who cross without parents or guardians are typically directed to resettlement agencies in the U.S.

Over the past year the administration has aggressively pushed to restrict asylum at the southern border, citing the need to impose a consequence on those who might not have valid claims.

Citing concerns over violations of due process and international law, immigrant advocates have challenged the legality of such restrictions -- which includes barring Central American migrants if they passed through another country without seeking asylum there first.