Al-Marri admitted meeting the alleged 9/11 mastermind
An al-Qaeda sleeper agent has been jailed in the US for plotting to provide material support for terrorism.
Ali al-Marri was held two months after the 9/11 attacks. He admitted having regular contact with Khalid Sheikh Mohammed, the alleged mastermind.
Al-Marri, a dual Saudi-Qatari national, pleaded guilty in May, having spent about six years in US custody.
Jailing him for eight years, the judge said he considered it likely al-Marri would attack the US if he could.
US District Judge Michael Mihm said he did not believe al-Marri's contrition.
However, he did not give him the maximum of 15 years in prison, saying he deserved credit for enduring harsh treatment while in custody.
Tearful court appearance
Defence lawyers said al-Marri spent time in isolation, had suffered sensory deprivation and threats to harm his family.
Al-Marri wept in court on Thursday as he said he was sorry he had ever helped al-Qaeda.
He admitted that he trained in al-Qaeda camps and stayed in al-Qaeda safe houses in Pakistan between 1998 and 2001.
He entered the US on 10 September 2001 on a student visa.
While studying, he carried out research into poisons and the location of US dams, waterways and tunnels, prosecutors said.
He was arrested in December 2001 and charged with credit card fraud.
In 2003 the Bush administration labelled him an "enemy combatant" and held him in a military base in South Carolina.
In December 2008 the Supreme Court agreed to review the legality of his detention.
But two months later, after President Barack Obama took office, he was formally charged by a federal court with supporting a foreign terror group.