concerns it will open the floodgates and leave the U.S. vulnerable to similar suits. A bipartisan group of lawmakers backed the 9/11 families bill.

The president, in a statement explaining the veto on Friday, said he has "deep sympathy for the families of the victims of the terrorist attacks of September 11, 2001 (9/11), who have suffered grievously. I also have a deep appreciation of these families' desire to pursue justice and am strongly committed to assisting them in their efforts."

However, the measure would "invite consequential decisions to be made based upon incomplete information and risk having different courts reaching different conclusions about the culpability of individual foreign governments and their role in terrorist activities directed against the United States — which is neither an effective nor a coordinatedcourt and win there," he said.

Before Friday, Obama had previously issued 11 vetoes during his presidency according to Senate records— none of which had been overturned.

In comparison, George W. Bush issued 12 vetoes during his tenure, four of which were overturned during his last two years in office as he saw his popularity plummet. Bill Clinton issued 36 vetoes with two overridden and George H.W. Bush issued 29 vetoes with just one overridden.