WASHINGTON — A Saudi detainee who remains stranded at the Guantánamo Bay wartime prison even though he was supposed to have been repatriated last month under the terms of a plea deal is accusing his government of dragging its feet.

“It’s shameful,” the detainee, Ahmed Muhammed Haza al-Darbi, said in an unusual statement conveyed Wednesday through his lawyer. “Unlike other countries, the Saudi government never even provided me with an attorney all these years.”

Mr. Darbi added: “And now my own government is an obstacle to my repatriation. What kind of country abandons its citizens in the custody of another government for 16 years? My country won’t take a step that was agreed on four years ago so that I can finally go home. It’s been my daily dream for four years to see my wife and children.”

A spokeswoman for the Saudi Embassy in Washington did not respond to a request for comment.

Charged before a military commission, Mr. Darbi agreed in February 2014 to plead guilty to terrorism-related offenses involving a 2002 Qaeda attack on a French-flagged oil tanker. Under the pretrial agreement, if he cooperated, he was to go home after four years to serve the remainder of his sentence in Saudi custody.