File photo of US President Barack Obama. [Photo/Xinhua]

WASHINGTON -- US Congress voted on Wednesday to override President Barack Obama's veto of a bill allowing families of the victims of the Sept 11 terror attacks to sue Saudi Arabia.

The vote handed Obama the first veto override during his nearly eight-year presidency, dealing a blow to the White House and highlighting the administration's waning sway over Congress during Obama's last months in office.

The US House of Representatives voted 348-77 to override the veto issued by Obama last week, hours after the Senate voted 97-1 in favor of the override, with Senate Minority Leader Harry Reid voting solely to sustain the veto.

The bill, named Justice Against Sponsors of Terrorism Act (JASTA), now becomes law despite the fierce opposition from the Obama Administration. Many lawmakers are reluctant to oppose a bill supported by families of the Sept. 11 attacks victims, as the election is just over a month away.

"Overriding a presidential veto is something we don't take lightly," said Democratic Senator Charles Schumer, one of the chief sponsors of the bill. "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."

"This bill is about respecting the voices and rights of American victims," Republican Senator John Cornyn said.

Following the Senate vote, White House spokesman Josh Earnest slammed the vote as "embarrassing."

"This is the single most embarrassing thing the United States Senate has done possibly since 1983," Earnest told reporters, referring to Senate's overwhelming override of former President Ronald Reagan's veto of a land bill.

"To have members of the United States Senate only recently informed of the negative impact of this bill on our servicemembers and our diplomats is in itself embarrassing," he added.