WASHINGTON (AP):

Supporters of the Iran nuclear deal are on the cusp of clinching the necessary US Senate votes to keep the contested agreement alive and hand President Barack Obama a major foreign policy victory, in spite of furious opposition.

Democratic Senators Bob Casey and Chris Coons yesterday became the 32nd and 33rd senators to announce support for the deal, just one shy of the 34 votes needed to uphold an Obama veto of Republican legislation aimed at blocking the agreement.

"This agreement will substantially constrain the Iranian nuclear programme for its duration, and compared with all realistic alternatives, it is the best option available to us at this time," Casey said in a statement. In remarks at the University of Delaware, Coons said: "I will support this agreement despite its flaws because it is the better strategy for the United States to lead a coalesced global community in containing the spread of nuclear weapons."

Earlier yesterday, Senator Ben Cardin, top Democrat on the Foreign Relations Committee, predicted that Obama would get to 34 votes by week's end.

Republicans in Congress and on the presidential campaign unanimously oppose the deal, which aims to curb Iran's nuclear programme in exchange for relief from economic sanctions.

The Israeli government is vehemently against it, contending concessions made to Iran could empower that country, which has sworn to destroy Israel.

But critics have failed to use Congress' summer recess to turn the tide against the agreement, despite a multimillion-dollar lobbying campaign funded by the powerful American Israel Public Affairs Committee, or AIPAC.