NEW YORK, United States (AFP) — Osama bin Laden’s son-in-law and former al-Qaeda spokesman was jailed for life yesterday after a US judge warned he remained a deadly threat to American citizens.

Kuwaiti national Sulaiman Abu Ghaith, 48, was handed the sentence after being convicted by a federal court in New York in March of plotting to kill Americans and providing material support to terrorists.

Before the sentencing, Abu Ghaith — who had applauded the September 11, 2001 attacks in propaganda videos after the strikes — spoke in Arabic through a translator to say the only judgment he would accept was that of God.

“Today when you are shackling my hands, and intend to bury me alive, you are unleashing the hands of hundreds of Muslims and they will join the rally of free men,” he said, dressed in a dark prison outfit.

Judge Lewis Kaplan said Abu Ghaith failed to show remorse for the September 11 attacks which left nearly 3,000 people dead, and told the courtroom he remained a menace.

“You continue to threaten,” Kaplan said. “You sir, in my assessment, still want to do everything you can to carry out al-Qaeda’s agenda of killing Americans.”

“What you have done warrants the maximum sentence,” he added.

US Attorney General Eric Holder hailed the judgment, and promised Abu Ghaith would “never again set foot outside a prison cell”.

Abu Ghaith is the highest-ranking Al-Qaeda operative ever held in a prison on US soil.

The alleged mastermind of the attacks, Khalid Sheikh Mohammed, is currently in US custody in Guantanamo Bay alongside four suspected co-conspirators.

They could face the death penalty if convicted.