Ahmed Omar Abu Ali, a 25-year-old US citizen who was born to a Jordanian father and raised in Falls Church, Virginia, faced a mandatory minimum of 20 years in prison and a maximum of life behind bars. He was convicted in November of conspiracy to assassinate the president, conspiracy to hijack aircraft and providing support to al-Qaida, among other crimes.

Prosecutors had argued for a life sentence.

Prosecutor David Laufman said: "The facts of this case are still astonishing. Barely a year after September 11 the defendant joined the organisation responsible for 3000 deaths."

But Gerald Bruce Lee, the district judge ,said 30 years was sufficient punishment. He compared the Abu Ali case to John Walker Lindh, who received a 20-year sentence.

Abu Ali's actions "did not result in one single actual victim. That fact must be taken into account," Lee said.

Saudi authorities arrested Abu Ali in June 2003 as he was taking final exams at the Islamic University of Medina. Abu Ali confessed that he joined al-Qaida while studying in Saudi Arabia and said he discussed with some of the most senior al-Qaida members plots, including Bush's assassination and plans to establish an al-Qaida cell in the US.

Abu Ali claimed that the Saudis had extracted a confession from him through torture and argued that the US was complicit in his torture by colluding with the Saudis. Prosecutors denied he was mistreated.

Torture

Abu Ali said he had the scars on his back that proved he was whipped or beaten by the Saudis. Pictures were taken of his back, and doctors for both the government and the defence examined him, coming to different conclusions.

In February, defence lawyers asked for a review of the conviction in light of revelations that the Bush administration had implemented a controversial warrantless eavesdropping programme.

Defence lawyers had no firm evidence that Abu Ali had been a target of the surveillance programme, which some argue is illegal. But they suspected it was likely given the government's belief that Abu Ali was an al-Qaida member and his domestic ties.

The government's response was not made public, but Lee decided to go ahead with the sentencing hearing after receiving the response. He had previously told defence lawyers he would schedule a hearing if prosecutors revealed anything requiring review. He scheduled no such hearing.