WASHINGTON (Reuters) - U.S. House Speaker Paul Ryan did not immediately endorse a Senate bill on Tuesday that would allow Americans to sue the government of Saudi Arabia over the Sept. 11 attacks, saying it should be reviewed to ensure it would not hurt diplomatic relations. With President Barack Obama traveling to Saudi Arabia  Tuesday, lawmakers have been discussing the “Justice Against Sponsors of Terrorism Act,” which passed the Senate Judiciary Committee in January but has not been scheduled for debate in the full Senate or the House of Representatives. “I think we need to review it to make sure that we’re not making mistakes with our allies and that we’re not catching people in this that shouldn’t be caught up in this,” Ryan, a Republican, told reporters. Some U.S. citizens whose relatives were killed in the 2001 attacks want to be able to sue Saudi Arabia because most of the 19 hijackers were Saudi nationals. The al Qaeda militant group, then based in Afghanistan, was blamed and the United States and its allies invaded the country. No U.S. investigation to date has reported finding evidence of Saudi government support for the attacks. White House spokesman Josh Earnest said Obama did not support the legislation and would not sign it. Obama will seek to reassure Gulf allies about Washington’s support on his trip. Some lawyers working with the Sept. 11 victims’ families have insisted that the bill would come up for a vote quickly and easily pass Congress. But Senate Majority Leader Mitch McConnell, a Republican, said no vote has been scheduled. Senate aides said there was at least one Republican “hold” on the measure. “I’m still looking at it,” McConnell told reporters, calling the measure an “important” bill. Republican Senator Bob Corker, chairman of the Senate Foreign Relations Committee, said lawmakers and the Obama administration were trying to resolve concerns about whether individuals should be able to sue foreign governments. “There are some sovereign immunity issues that need to be worked through,” Corker said. He declined to comment on whether he supported the legislation, because the bill has not been finalized. The New York Times reported on Friday that Saudi Foreign Minister Adel al-Jubeir told U.S. lawmakers his country would be forced to sell up to $750 billion in U.S. assets in response to the bill if it passed. Several members of Congress and senior aides said they were unaware of any such threat, outside of the newspaper’s report. Democratic Senator Chuck Schumer, a lead bill sponsor said the Saudis had not talked to him about that threat. But he, and other senior Democrats said they wanted the bill to move ahead despite the White House’s objections. “If the Saudi government was complicit in terrorism, and a trial so determines, it would be a real deterrent to other governments not to be complicit in terrorism,” said Schumer, who represents New York, the state hardest hit in the attacks. Corker said he had been in close contact with the administration, but had not discussed the bill with Saudi officials for some time. Ryan said the bill did not come up while he was on a visit to Riyadh. Republican Senator Chuck Grassley, the chairman of the Judiciary Committee who supports the bill, said it was tied up  by State Department concerns about sovereign immunity. “I think Americans need some redress when they’re hurt.” 