Military lawyers appointed to defend alleged terrorists being held by the US at Guantanamo Bay have expressed growing unease, according to reports.
None of the detainees have yet been charged
The UK's Guardian newspaper says that a team of lawyers was dismissed after complaining that the rules for forthcoming trials were unfair.
New York's Vanity Fair magazine reports that some of the lawyers say their ethical obligations are being violated.
The Pentagon has strongly denied the media reports.
About 660 prisoners are being held at the US military base in Cuba, including nine Britons.
They have not been charged or allowed access to lawyers, and their detention has been condemned both by human rights groups and allies of the US. Most were picked up two years ago following the fall of the Taleban regime in Afghanistan.
The Guardian quotes a source close to the military legal establishment as saying that a team of lawyers assigned to the detainees has been dismissed after complaining about the way the planned military tribunals have been designed.
Demonstrators have called for justice for the detainees
The rules include allowing government representatives to monitor conversations between the lawyers and their clients.
A group of lawyers told Vanity Fair magazine that such rules made a fair trial for the detainees impossible. They are planning a lawsuit against the government, arguing that they were given unlawful orders, the magazine reports.
But the US Defence Department said the magazine's claims were unfounded.
'Monstrous failure of justice'
The Pentagon announced on Tuesday that a US-born "enemy combatant" being held a naval prison in South Carolina would be allowed access to a lawyer subject to appropriate security restrictions.
Yasser Esam Hamdi, was detained by US forces in Afghanistan two years ago and originally taken to Guantanamo Bay, but he was moved to the naval prison when it was determined that he was a US citizen.
Last month one of Britain's top judges, Lord Justice Steyn, condemned the detentions at Guantanamo Bay as "a monstrous failure of justice".
The judge said the detainees were being deliberately held beyond the rule of law and the protection of any courts.
And in October, a former US appeals court judge, John Gibbons, told BBC News Online that justice was being "totally denied" to the detainees in Guantanamo.
"They don't have access to lawyers; they have had no hearings; they are just in limbo. That's as clear an example of justice denied as you can find," he said.
US authorities reportedly plan to release at least 100 inmates from Guantanamo Bay detention camp later this month, but few details have been released.
The US has already released 88 inmates - although many were re-arrested in their home countries.