Image copyright Al Jazeera Image caption Abu Ghaith appeared alongside Bin Laden in a video just one day after the 9/11 attacks

Osama Bin Laden's son-in-law Sulaiman Abu Ghaith, who was an al-Qaeda spokesman after 9/11, has been convicted of terrorism-related charges at a trial in New York.

He could face life in prison when he is sentenced in September for conspiracy to kill Americans and aiding al-Qaeda.

The Kuwaiti clergyman was captured in Jordan last year and brought to the US.

He is the highest-ranking al-Qaeda figure to face trial on US soil since the attacks.

The jury returned a guilty verdict on three charges: conspiracy to kill Americans, conspiring to provide support to al-Qaeda, and providing support to al-Qaeda. The verdict came after about five hours of deliberation.

Videos showing Abu Ghaith threatening America with no end to the "storm of airplanes'' were shown to jurors, but he argued his role was a purely religious one, aimed at encouraging all Muslims to rise up against their oppressors.

He testified that Bin Laden had asked him to be al-Qaeda's spokesman on the night of the 9/11 attacks.

Image copyright AP Image caption In his surprise testimony, Abu Ghaith recounted the night of the 9/11 attacks, when Bin Laden met him in a cave and asked him: "Did you learn what happened? We are the ones who did it."

Image copyright Getty Images Image caption Abu Ghaith's defence lawyer argued there was "zero evidence" his client was involved in conspiracies

Image copyright Reuters Image caption In court, Abu Ghaith was repeatedly shown videos in which he called for more attacks on Americans

On Monday, during closing arguments, Assistant US Attorney John Cronan highlighted what he said was the importance of Abu Ghaith's post-9/11 status.

"Going to that man was the very first thing Osama Bin Laden did on September 11 after the terror attacks," he said. "The defendant committed himself to al-Qaeda's conspiracy to kill Americans, and he worked to drive other people to that conspiracy."

Denying he was an al-Qaeda recruiter, Abu Ghaith insisted he had agreed to meet with Bin Laden in a cave on the night of September 11 out of respect for Bin Laden's standing as a sheikh.

One witness at the trial was a British man who was supposed to join Richard Reid in the attempted shoe-bomb airline attack of December 2001. The man left the plot after his parents warned him against involvement in terrorism.

He did not know Abu Ghaith, but prosecutors introduced evidence to show Abu Ghaith knew of such detailed plans for more air attacks on the US, as he promised in his videos.

Abu Ghaith's defence lawyers argued there was "zero evidence" that the 48-year-old former teacher knew about any conspiracies and that the prosecution case was based purely on "ugly words and bad associations."

In a surprise move, the cleric took the witness stand in his own defence, denying he helped plot al-Qaeda attacks and claiming he never became a formal member of the group.

Abu Ghaith, who is one of the highest-ranking al-Qaeda linked figures to face a civilian jury on terrorism-related charges, is married to Bin Laden's eldest daughter Fatima.

Bin Laden, a founder of al-Qaeda, was killed by US forces in May 2011 at his hideout in Pakistan.

As in several other terrorism trials held in American civilian courts, the jury remained anonymous.