President Obama is under new pressure from families of Sept. 11, 2001 terror attack victims who want him to back legislation allowing them to sue the Saudi government.

The controversy picked up new urgency this month after a "60 Minutes" investigation that looked at possible links between Saudi officials and the 9/11 hijackers, which revealed that information may be in a classified section of a Congressional report.

Saudi Arabia - a key U.S. ally - has threatened to retaliate financially if the bill becomes law and administration officials have been lobbying to kill the legislation, but that has made many 9/11 families very angry, reports CBS News correspondent Chip Reid.

"I'm completely outraged," said Loria Van Auken, who is among those convinced that the 9/11 hijackers were helped by Saudi agents. Her husband Kenneth worked on the 105th floor of the World Trade Center's North Tower.

For years, Van Auken and other 9/11 families have tried to hold the Saudi government accountable in federal court. But because foreign governments are immune from suits in the U.S., their efforts have so far failed.

"If someone you loved was murdered and the person was just able to go away Scott free, would you be okay with that? I don't think anybody would," Van Auken said.

Congress is now considering a bill to permit lawsuits against countries that "contribute material support or resources" for "acts of terrorism."

The Obama administration said the proposed legislation could lead to retaliation overseas. Saudi Arabia has already warned it will dump hundreds of billions of dollars in U.S. assets if the bill becomes law.

"It feels like blackmail," Van Auken said. "The government, the president is siding with Saudi Arabia over the 9/11 families."

On last Sunday's "60 Minutes," correspondent Steve Kroft reported on a classified portion of the 9/11 report kept locked away in a secret vault. According to former government officials, the 28 heavily redacted pages contain details about a possible Saudi support network for the hijackers while they were in the U.S.

"I think it is implausible to believe that 19 people -- most of whom didn't speak English, most of whom had never been in the United States before, many of whom didn't have a high school education-- could've carried out such a complicated task without some support from within the United States," Bob Graham, former chairman of the Senate Select Committee on Intelligence, told Kroft.

"And you believe that the 28 pages are crucial to this?" Kroft asked.

"I think they are a key part," Graham said.

Van Auken wants those pages released to the public.

"It's hard to have a case when you can't see your own evidence," Van Auken said.

All this comes as President Obama leaves for Saudi Arabia Tuesday. It's possible this issue will be brought up when he meets with King Salman.

The royal embassy of Saudi Arabia did not respond to a request for comment from "CBS This Morning" but last week, it said: "The 9/11 commission confirmed that there is no evidence that the government of Saudi Arabia supported or funded Al Qaeda."