WASHINGTON — Within hours of an announcement Thursday afternoon that a bipartisan group of senators had introduced new legislation to increase sanctions against Iran if ongoing talks prove unsuccessful, American Jewish groups voiced their support for the initiative.

A number of major Jewish organizations welcomed the Nuclear Weapon Free Iran Act as complementary to diplomatic initiatives and called for even greater Senate support for the bill, which faces an uphill battle against the administration.

“We believe a diplomatic solution to prevent Iran from acquiring a nuclear weapons capacity, a threat to the entire world, is vital. We stand firmly with President Obama as he and our P5+1 allies seek to negotiate a comprehensive agreement,” said Michael Siegal, chair of the Jewish Federations of North America (JFNA) Board of Trustees.

“We recognize economic sanctions have been successful in bringing Iran to the negotiating table, as well as in expressing the resolve of the global community,” Siegal added. “The threat of additional sanctions, with the appropriate Presidential waivers in this legislation, ensures that Iran knows this and all other options are on the table should negotiations fail.”

Supporters say the bill preserves presidential authority by allowing the president to waive future sanctions either by certifying Iranian compliance with the interim agreement reached in Geneva, or in the event that a final agreement is reached. At the same time, it sets basic terms for a deal, mandating that a final arrangement must dismantle Iran’s nuclear infrastructure.

JFNA representatives emphasized that the Senate bill is in line with a resolution passed last month by the Jewish Federations, in which the body called for the “complete dismantling of Iran’s capability of producing nuclear weapons.”

The Jewish Federations encouraged Senators to co-sponsor the legislation, and to swiftly pass it upon their return to Washington in January.

The Anti-Defamation League (ADL) also welcomed the bill, but urged Congress to work with the administration as the bill moves forward — a particularly tall order given Obama’s promise to veto the bill if it reaches his desk.

In contrast to the administration’s position that the bill would undermine diplomatic efforts, Barry Curtiss-Lusher, ADL National Chair, and ADL National Director Abraham H. Foxman wrote in a statement Thursday that the proposed legislation “further enhances the American strategy of tough sanctions in support of our negotiation efforts.”

“By putting in place broader and deeper sanctions that would kick in after a year, the legislation makes clear to Iran the severe economic price it will pay if it does not negotiate seriously and plays for time. It also gives the administration time to pursue negotiations to end Iran’s nuclear weapons program,” they continued.

The ADL highlighted the Obama administration’s initiative last week to enforce existing sanctions, commenting that “the administration has also sent a message to those who may think now is the time to pursue new business opportunities with Iran by announcing a series of enforcement actions last week against entities found to be evading sanctions against Iran and providing support for its nuclear program.”

The organization tread a fine line between criticizing and supporting the White House, noting that “both branches of government have vital roles to play,” but also adding that, in contrast to the administration’s allegations, “far from being a step which will make war more likely, as some claim, enhanced sanctions together with negotiations will sustain the utmost pressure on a regime that poses a threat to America and our closest allies in the Middle East and offer a greater chance of achieving success through diplomacy.”

The Jewish Council for Public Affairs also released a statement in which it “encouraged the Senate to pass the Nuclear Weapon Free Iran Act,” which was sponsored by Senators Robert Menendez (D-NJ) and Mark Kirk (R-IL), and introduced with 24 co-sponsors, including a dozen Democrats.

The JCPA, a Jewish umbrella organization, described the legislation as “an important contribution toward a successfully negotiated end to Iran’s nuclear program.”

The Nuclear Weapon Free Iran Act would further restrict purchases of Iranian petroleum products and apply new penalties to other parts of Iran’s economy, including its engineering, mining and construction sectors. It proposes that new sanctions would come into effect should Iran violate the interim Joint Plan of Action agreed to in Geneva last month, or should the talks fail to reach a final agreement.

The legislation also includes a non-binding provision that the US will support Israel if it takes “military action in legitimate self-defense.” Although it was initially suggested that the provision constitutes approval of military action, bill proponents noted that the language is phrased in a way that is traditionally accepted as non-binding on Congress.