A day after voting to override President Barack Obama's veto of a 9/11 bill that would allow families to sue Saudi Arabia, lawmakers expressed concern of the possible unintended consequences of the bill.

Senior leaders noted that the bill could open the door to reciprocal lawsuits and place Americans abroad at risk of lawsuits by foreign governments.

"It appears as if there may be some unintended ramifications," Senate Majority Leader Mitch McConnell, a Kentucky Republican, said on Thursday (29 September). "I do think it's worth further discussing."

President Obama vetoed the controversial bill on 23 September, arguing that the legislation could endanger US intelligence officials and diplomats by weakening sovereign immunity, the Wall Street Journal reported.

Sovereign immunity protects national governments from lawsuits against their will. However, Congress members overwhelmingly voted to override Obama's veto on Wednesday (28 September).

Now, facing the possible repercussions of their decision, lawmakers said they might work on the bill when they return to Washington DC following the presidential election.

House Speaker Paul Ryan, a Wisconsin Republican, noted Congress may need to fix the Justice Against Sponsors of Terrorism Act (JASTA) to protect US troops from legal repercussions while still allowing 9/11 victims and their families to pursue legal action against Saudi Arabia.

"There will be an attempt to narrow the effect of what we've done," Senate Foreign Relations Committee Chairman Bob Corker, a Tennessee Republican, said. Corker said lawmakers may consider limiting the bill's purview to the 9/11 attacks or establishing a committee of experts to determine "if there was culpability there".

However, Senator Charles Schumer, a New York Democrat, and Senator John Cornyn, a Texas Republican, refuted the idea of confining the bill to just the 9/11 attacks. "That tells the Saudis, 'go ahead and do it again and we won't punish you,'" Schumer said, according to the Wall Street Journal.

Schumer, one of the bill's main sponsors, said he would look at any proposal but it had to be "... something that doesn't weaken the bill and limit the right of these families to get their day in court and justice" to receive his approval.

Saudi Arabia, which is strongly against the legislation, has denied any role in the 9/11 attacks. Fifteen of the 19 hijackers of the 2001 attacks were from Saudi Arabia. The country's Ministry of Foreign Affairs said it hoped "wisdom will prevail" and that "Congress will take the necessary steps to correct this legislation".

Meanwhile, Republicans blamed Obama for failing to inform them early in the bill's process of the possible unintended consequences. "By the time everybody seemed to focus on the potential consequences, members had already basically taken position," McConnell said, according to NBC News.

White House press secretary Josh Earnest shot back by noting that lawmakers were showing "rapid onset buyer's remorse" over the "terrible mess that they have made". Earnest noted that lawmakers received several letters from Obama, Central intelligence Agency Director John Brennan and others.

"Ignorance is not an excuse, particularly when it comes to our national security," he said.