The latest poll on the Iran nuclear deal found that President Barack Obama has not yet won the support of a large majority of American voters.

Only 28 percent of Americans told Quinnipiac University they approve of the Iran deal, which was brokered between Iran and six world powers and aims to curb Tehran's nuclear program in exchange for sanction relief. Fifty-seven percent said they oppose the deal.

Eighty-six percent of Republicans said they are against the deal, with only 3 percent in favor. Most independents also oppose the deal, 55 percent to 29 percent, while only a slight majority of Democrats said they support the deal, 52 percent to 32 percent.

The poll also found most voters, 56 percent to 35 percent, said they disapprove of how Obama is handling the situation in Iran.

When respondents were asked whether they think the nuclear deal would make the world safer or less safe, 58 percent said less safe and 30 percent said safer.

The survey was conducted by telephone July 26-30 among 1,000 adults, and carries a margin of error of 3.1 percentage points.

A Pew Research Center survey from last month found similar discontent over the deal, with 48 percent disapproving and 38 percent approving, and a CNN/ORC poll from last week found 52 percent of respondents said they want Congress to vote against the deal, while 44 percent want Congress to approve it. However, Washington Post-ABC and Economist/YouGov polls from last month both found a small majority of Americans support the accord.

The findings suggest the debate could go either way when Congress comes back from summer break in September to approve or reject the deal. Given the overwhelming Republican opposition, lawmakers are expected to propose a resolution of disapproval, but since Obama has vowed to veto such an effort to compromise the deal, unless critics can obtain the 290 votes in the House and 67 in the Senate needed to override a veto, the deal will stand.