US President Barack Obama drew another stinging rebuke over the Iran nuclear deal, with a Republican senator stating that the agreement failed to meet Obama's core objectives of making the world safer for Americans and their allies.

In her GOP Weekly Address over the weekend, Sen. Shelley Moore Capito said what was agreed between Iran and the Obama administration was a "bad deal" as she disputed the administration's claim that it will improve the safety, security and stability of the Americans.

"Because the president operated from a position of concession and not of strength, the American people are left with a bad deal. The President has said that sanctions will go back into effect if Iran violates this agreement, but let's be clear, reversing course will be next to impossible,'' she said.

"The bipartisan majority of Congress and the American public have concluded it will not improve our safety, our security and out stability. The partisan minority in Congress who support the deal acknowledge its shortcomings, and the litany of flaws raised throughout this debate should invoke serious concerns about our entering into this agreement with Iran,'' said the West Virginia Republican.

She said Congress came up with the conclusion after careful and thorough examination on the details of the President's agreement with Iran, which was supposed to make America safer and eliminate Iran's path to nuclear weapon.

During her visit to the Middle East in the spring, Capito said she heard firsthand from world leaders about the dangers posed by a nuclear Iran. She added that Iran's supreme leader even had the gall to say that "even after this deal, our policy toward the arrogant US will not change.''

The senator also believes that providing tens of billions of dollars to Iran will only "increase its ability to sponsor the Syrian regime, support Hezbollah and threaten our allies," Newsmax reported.

She said the US should have first secured Iran's commitment that it will recognise Israel, one of its key allies in the region, and ensure the release of four American citizens languishing in Iranian prisons.

Iran is not a credible player, she said, noting that it remains the world's largest state sponsor of terrorism.

She said stronger sanctions could have forced the Iranians to accept a better agreement that is in the best interests of America and the world.

However, whatever critics say, the Iran nuclear deal is a done deal after the Senate Republicans failed to kill it last week.

By a 56-42 vote, the Republican-majority Senate fell four votes short of the required 60 needed to advance the measure to scrap the deal in the 100-member chamber.

With no more Senate votes slated this week, the result ensured that the US Congress will not pass a resolution of disapproval that would have rendered the deal useless by depriving Obama of his ability to waive the sanctions imposed on Iran.