60 children detained as prisoners at Guantanamo

Those detainees were under 18 when they were captured by US forces, and at least 10 of them still being held at Guantanamo were 14 or 15 when they were seized, held in solitary confinement, subject to repeated interrogation and allegedly tortured, the charity Reprieve was reported as saying.

Britain's Independent on Sunday (IoS), which carried the allegations, suggested the charges could threaten the United States' relationship with its closest ally in the "war on terror", Britain.

"We would take a very, very dim view if it transpires that there were actually minors there," it quoted a British government official as saying.

Unnamed government sources said the allegations directly contradicted Washington's assurances to London that no minors were held at Guantanamo.

Reprieve's legal director and a lawyer for a number of detainees, Clive Stafford-Smith, told the newspaper the United States could have broken not only its own laws but all human rights conventions by putting children in adult jails.