An Australian judge on Thursday rejected an appeal by former U.S. Marine Corps pilot Daniel Duggan to avoid extradition to the United States over allegations that he illegally trained Chinese military aviators more than a decade ago.

Duggan is accused of training Chinese military pilots while working as an instructor for the Test Flying Academy of South Africa. Duggan has denied the allegations, contending they were political posturing and that the U.S. was unfairly singling him out.

Federal Court Justice James Stellios ruled in dismissing the appeal that no jurisdiction error was made in 2024 by then Attorney-General Mark Dreyfus in ordering Duggan's extradition.

Duggan's wife and mother of his six children, Saffrine Duggan, told reporters outside the court in Canberra that his lawyers would consider a further appeal. Lawyers are also asking Dreyfus's successor as attorney-general, Michelle Rowland, to reverse the extradition order.

"We are very disappointed by this ruling and we will consider our options carefully. But make no mistake, we will not give up," Saffrine Duggan said. "Today does not end our search for justice."

Rowland's office noted the court ruling and said in a statement Daniel Duggan would "remain in extradition custody in Australia until his surrender to the United States."

A 2016 indictment from the U.S. District Court in Washington, which was unsealed in late 2022, alleges Duggan conspired with others to provide training to Chinese military pilots in 2010 and 2012, and possibly other times, without applying for an appropriate license.

Prosecutors allege Duggan received about nine payments totaling around 88,000 Australian dollars ($61,000) from another conspirator as well as travel to the U.S., South Africa and China for what was sometimes described as "personal development training."

Duggan, who is 57 and was born in Boston, has been held in maximum security prisons since he was arrested in 2022 at a supermarket near his family home in New South Wales.

Duggan lived and worked in China for about five years before his arrest, corporate records showed.

He served in the U.S. Marines for 12 years before migrating to Australia in 2002. He gained Australian citizenship in January 2012, giving up his U.S. citizenship in the process.