An Afghan woman living in Texas with legal US permanent residency has been deported from the country in the first-ever use of a secretive court.

Nazira Haji Zada, 47, chose to leave the US rather than continue to argue her case before the Alien Terrorist Removal Court, according to the US Department of Justice (DOJ) and her lawyers.

The Alien Terrorist Removal Court was created in 1996, but had never heard a case before the proceedings in July. It is meant for non-US citizens facing terrorism-related charges when the evidence is confidential and related to national security.

Lawyers for Haji Zada argued that the case violated her right to due process under the US Constitution.

Afghanistan citizen Haji Zada was never charged with a crime, but prosecutors had tried and convicted her son and son-in-law for terror offenses.

Her son, Abdullah Haji Zada, and son-in-law, Nasir Ahmad Tawhed, were both found guilty of a plot to carry out a mass shooting on Election Day in 2024, inspired by the group calling itself Islamic State.

Haji Zada, who has been living in Fort Worth, Texas, was accused by prosecutors of being the "matriarch" of the group, who had worked "to radicalize the family".

In a statement on Friday, the justice department said she "conceded that she is an alien terrorist and waived appeal of the removal order, terminating her previous [immigration] status".

"This landmark case, resulting in the prompt removal of this alien terrorist to her country of origin, is a win for national security and the rule of law," said US Attorney General Todd Blanche.

"Those who support and condone terrorism should not be living in the United States, and this first-ever case before the ATRC shows how the Department will use every tool at its disposal to protect our country."

Court-appointed lawyers for Haji Zada said they were denied access to the evidence in her case.

"Our client's choice to consent to removal should not be seen as an endorsement of this court's legitimacy," public defenders Matthew Farley and Mary Manning Petras said in a statement to The Washington Post.

"Dragging lawful permanent residents into court but refusing to show them or their attorneys the evidence that will be used against them is a plain violation of due process. We are confident that the Alien Terrorist Removal Court will be struck down as unconstitutional as soon as a judge is asked to address the issue," they said.