WASHINGTON — The European Union urged President Barack Obama on Wednesday to block a bill that would allow survivors of the 9/11 terror attacks to sue Saudi Arabia, calling it a rolling back of the principle of sovereign immunity that could lead to reciprocal action.

The statement, released by the EU delegation to the United States, said any dilution of sovereign immunity could lead to reciprocal action by other states and “put a burden on bilateral relations.”

“State immunity is a central pillar of the international legal order,” the EU said. “The European Union is of the view that the possible adoption and implementation of JASTA would be in conflict with fundamental principles of international law.”

The bill, which earlier this year flew through the House and Senate, has lost some support in the face of protests and strong opposition from the White House. Advocates say it will provide justice for survivors, while others caution against a precedent that could open officials to retaliation from abroad.

On Tuesday, protesters rallied outside the White House with signs that read “Override Veto” and “Congress Stay in D.C.” Terry Strada, national chairwoman for 9/11 Families & Survivors United for Justice Against Terrorism, organized the demonstration.  About 100 people turned up to support the bill.

“Nine-eleven families have been fighting for justice for over 15 years and this bill will simply allow us to present the evidence that we have against Saudi Arabia in a courtroom,” Strada said. “As long as (America) does not support terrorist organizations there is no reciprocal lawsuit that can happen as a result of JASTA.”

Strada, whose husband died in the attacks in New York, added that no nation should have immunity for waging war on American soil. She said she would remain in Washington through the week to lobby lawmakers and ensure a successful override vote.

House Speaker Paul Ryan said on Wednesday that he expects the House to override a veto. Yet, at the same time, he expressed concern for future legal precedent.

“I worry about legal matters,” Ryan told reporters. “I worry about trial lawyers trying to get rich off of this. And I do worry about precedence. At the same time, these victims need to have their day in court.”

For Obama to sustain his likely veto, the president needs at least 34 senators to oppose an override attempt. Sen. Kirsten Gillibrand, D-N.Y., Wednesday told the Medill News Service she remains in full support of the bill and said she does not think Obama has enough votes to sustain a veto.

However, Illinois Sen. Dick Durbin — the second-ranking Democrat on the Judiciary Committee — said he had not yet determined what he will do and has no idea if a veto can be sustained.

Speaking to reporters in New York on Tuesday, White House press secretary Josh Earnest admitted the administration had a “steep hill to climb,” but vowed to continue the fight.

“The United States benefits from sovereign immunity more than any other country in the world,” Earnest said. “And to pass a piece of legislation that would open up our diplomats and our service members and even American businesses to potential lawsuits in courts all around the world is foolish.”

Obama has until Friday to use his veto power.