Washington, DC - Saudi Arabia has asked a US judge to dismiss 25 lawsuits filed against it in relation to its alleged support of the September 11, 2001 attacks, court documents filed late on Monday afternoon show.

In a filing in US District Court in Manhattan, lawyers representing Saudi Arabia claim the plaintiffs - who represent thousands of victims who died and were injured in the attacks, as well as businesses and insurers - cannot prove the Gulf kingdom supported the al-Qaeda-affiliated men who hijacked and crashed planes into New York's World Trade Center, the Pentagon outside Washington, and a Pennsylvania field. Nearly 3,000 people died in the attacks.

Saudi Arabia also claimed it deserves sovereign immunity.

James Kreindler, a lawyer representing those killed in the September 11 attacks, told Reuters news agency the filing was "expected … We have tonnes of allegations of what many Saudis and the country's alter ego charities did. Saudi Arabia cannot hide from the facts."

Saudi Arabia's lawyers introduced several exhibits which they say support their claims. One such exhibit was an executive summary from the CIA dated to 2005, which says there was no evidence that Saudi Arabia supported the attackers.

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But doubt has long-centred over claims that Saudi Arabia wasn't involved. It is known that 15 of the 19 hijackers were Saudi citizens, and several met Saudi nationals with ties to their government, such as Omar al-Bayoumi, a Saudi national who has connections to Saudi diplomats.

A trove of declassified documents suggested evidence of collusion between the hijackers and Saudi Arabia described as "chilling" by investigators.

Congress initiated an inquiry on November 27, 2002 into the attacks. A report totalling over 1,000 pages was published in 2004. There were 28 pages left out of the report on the orders of former President George W Bush, which became a source of controversy.

These pages were finally made public in July 2016, though no definitive answers arose, and further possible ties between al-Qaeda and the Saudi embassy in the US were uncovered, as phone numbers saved in the phone of an al-Qaeda operative captured in Pakistan were linked to Saudi consulates in the US.

Former Senator Bob Graham, the co-chair of Congress's 9/11 Joint Inquiry and one of the voices alleging the Saudis and the hijackers were connected, told Politico he no longer called the US government's actions a "cover-up". That would be "a passive activity. What they're doing now I call aggressive deception."

The 25 cases were previously in danger of being thrown out, due to a legal inability for US citizens to sue foreign governments for support of "extremists".

Then, in 2015, legislators introduced the Justice Against Sponsors of Terrorism Act (JASTA), which made possible legal action against states that support "terrorists" who commit violent acts on US soil.

Then-President Barack Obama attempted to veto the bill after months of Saudi threats and lobbying, but the US Congress overrode Obama's veto in 2016. The override was widely praised as a step towards justice for the victims of the deadliest attack on US soil in history by much of the US public.

Lawyers for the plaintiffs have until October 2 to file documents in opposition to the motion.

Lawyers on both sides declined Al Jazeera's request for comment.