Congress has voted to override President Barack Obama's veto of a bill that would allow families of 9/11 victims to sue for damages from the Saudi Arabian government for the attacks.

Both chambers of Congress voted by an overwhelming margin to override the President's veto of the Justice Against Sponsors of Terrorism Act (JASTA), marking the first time Congress has successfully overruled a veto during Mr Obama's two terms.

Early on Wednesday afternoon, the Senate voted against the veto by 97 to one, with minority leader Harry Reid acting as the only dissenter. A few hours later, the House of Representatives voted 348 to 77.

"Overriding a presidential veto is something we don't take lightly, but it was important in this case that the families of the victims of 9/11 be allowed to pursue justice, even if that pursuit causes some diplomatic discomforts," said Democratic New York Senator Charles E Shumer, who co-authored the bill with Republican Texas Senator John Cornyn.

White House press secretary Josh Earnest called the vote "the single most embarrassing thing the Senate has done" in decades.

Mr Reid was the sole dissenter in the vote, while senators Bernie Sanders and Tim Kaine were absent.

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Mr Obama vetoed the bill on Friday, citing concerns that JASTA could open up US officials to foreign lawsuits.

"Removing sovereign immunity in US courts from foreign governments that are not designated as state sponsors of terrorism, based solely on allegations that such foreign governments' actions abroad had a connection to terrorism-related injuries on US soil, threatens to undermine these longstanding principles that protect the United States, our forces, and our personnel," Mr Obama wrote in his veto message to Congress.

Both the Senate and the House passed the bill unanimously in May.

Fifteen of the 19 hijackers who flew planes into the World Trade Centre and Pentagon in September 2001 were Saudi citizens, although Riyadh has denied having any role in supporting the attackers.

The 9/11 Commission found no evidence of Saudi involvement in the attacks.