|Warsame's questioning was conducted under the rules of the US Army Field Manual, US official says [Reuters]
A Somali man who has appeared before a US criminal court to face charges of assisting al-Qaeda and a Somali armed group was questioned secretly aboard a US Navy ship for more than two months without being advised of his rights.
Ahmed Abdulkadir Warsame was captured in the Gulf of Aden on April 19, where he faced questioning by US interrogators "for intelligence purposes for more than two months" before being read his Miranda rights, US prosecutors said in a statement.
Miranda rights entitle suspects to a lawyer and the right to remain silent.
Warsame appeared in a New York court on Tuesday and pleaded not guilty to providing material support to Al-Qaeda in the Arabian Peninsula (AQAP) and Somalia's al-Shabaab.
A US official said Warsame's questioning was conducted under the rules of the US Army Field Manual, which places strict limits on interrogation techniques.
Members of the High Value Interrogation Group - comprised of CIA, FBI and Defence Department staff - interrogated him, an official told AFP on condition of anonymity.
President Barack Obama's administration has come under fire by Republicans, and even some fellow Democrats, over his decision to prosecute some terrorism suspects in criminal courts and not in military courts, where rules for evidence are looser.
In Washington, another senior administration official said Obama's national security team had unanimously recommended the prosecution of Warsame in a criminal court.
After his interrogation, a fresh FBI team came in and was permitted to talk with Warsame, at which time he waived his legal rights and continued to talk for several days, an official, who wished to remain anonymous, told the Reuters news agency.
Warsame arrived in New York City late on July 4 after being formally arrested the previous day, according to a letter from prosecutors to the US court.
Warsame, said to be in his mid-20s, was indicted on nine charges, including providing material support from at least 2007 to April 2011 to al-Shabaab and AQAP, two groups designated by Washington as terrorist organisations.
According to the charges, Warsame also worked to broker a weapons deal with AQAP on behalf of al-Shabaab.
A joint statement by the Manhattan US Attorney, the FBI and the New York Police Department said he was also charged with "conspiring to teach and demonstrate the making of explosives, possessing firearms and explosives in furtherance of crimes of violence and other violations".