Morocco on Thursday denied any agreement with the United States that it would not detain a Moroccan repatriated after spending 13 years in the Guantanamo Bay military prison without charge.

Younis Abdurrahman Chekkouri, 47, has been in Moroccan custody since mid-September, when the United States released him from detention in Cuba and flew him home.

His lawyers say Morocco broke diplomatic assurances to the United States by detaining him but Moroccan Justice Minister Mustafa Ramid on Thursday denied any deal.

"It's true that we negotiated with Washington to bring Chekkouri to Morocco but we never gave any assurances on his release," Ramid said on the sidelines of a meeting with US Attorney General Loretta Lynch.

Lynch did not comment on the issue.

"Someone is just not telling the truth here," said Cori Crider, one of Chekkouri's lawyers from London-based human rights charity Reprieve.

"Either US State Department officials repeatedly deceived me and my client about Morocco's intentions when my client was in Guantanamo, or Moroccan officials have been making diplomatic promises freely and breaking them just as fast," she said.

Chekkouri is next due to appear in court on December 3, another of his lawyers, Khalil al-Idrisi, said.

The Moroccan was captured by Pakistani forces in late December 2001 with a group of several dozen Arab fighters who had fled the Tora Bora cave complex in eastern Afghanistan, a stronghold of the Taliban and its Al-Qaeda allies.

Transferred to Guantanamo in May 2002, he was never charged.

Following recent releases, 112 detainees remain in the prison opened to hold terror suspects following the September 11, 2001 attacks on the United States.

Authorities in Rabat have moved to counter what is seen as a growing jihadist threat by imposing heavier punishments -- including up to 10 years in jail -- for those found guilty of involvement in "terrorism-related activities".