Washington, (Agencies): A US appeals court recently upheld a life imprisonment sentence for an American citizen convicted in 2005 of plotting to kill then-President George W Bush and conniving with al Qaeda.

The US Court of Appeals for the Fourth Circuit, based in Virginia, refuted arguments by attorneys for Ahmed Abu Ali that the sentence was unreasonable and flouted various constitutional provisions.

Abu Ali, who was born in Texas and lived in the Washington suburb of Falls Church in Virginia, was held in 2003 while studying at a Saudi university and was arrested in Saudi custody for 20 months before being returned to the United States to face trial.

In Saudi Arabia, he signed confessions and made statements admitting to the plot against Bush and to having links to an al Qaeda cell. That provided the bulk of the US government's case against him.

Abu Ali initially was sentenced to 30 years jail, but the appeals court in 2008 sided with US Justice Department prosecutors and sent the case back for resentencing. He then received the maximum term of life in prison.

The US Attorney for the Eastern District of Virginia Neil MacBride said he was satisfied the appeals court supported the sentence for a man who conspired to murder Bush and other high-ranking US government and military leaders.