Former US Vice President Dick Cheney warned that the nuclear deal made by President Obama with Iran will likely lead to the first use of a nuclear weapon since 1945.

In a book he co-wrote with his daughter Liz, an excerpt of which was published in the Wall Street Journal on Friday, Cheney blasted Obama's foreign policy, saying "nearly everything the president has told us about his Iranian agreement is false."

Obama has been defending the agreement, saying it will prevent Tehran from acquiring nuclear weapons. However, Cheney said the deal "will actually facilitate and legitimise an Iranian nuclear arsenal."

"The Obama agreement will lead to a nuclear-armed Iran, a nuclear-arms race in the Middle East and, more than likely, the first use of a nuclear weapon since Hiroshima and Nagasaki," he said, referring to the US dropping of atomic bombs in the two Japanese cities in 1945, killing more than 200,000 people, thus forcing Japan to surrender in World War II.

Cheney contended that "allowing the Iranians to continue to enrich uranium and agreeing to the removal of all restraints on their nuclear program in a few short years virtually guarantees that they will become a nuclear-weapons state, thus undermining the fundamental agreement at the heart of the NPT [Non-Proliferation Treaty]."

Obama, through the Iran deal, will provide "a pathway for the world's worst state-sponsor of terror to acquire nuclear weapons," he said.

The Cheney also blamed Obama for the rise of the Islamic State and other terror groups because of the president's decision to withdraw American troops from Iraq in 2011.

"He has abandoned Iraq, leaving a vacuum that is being tragically and ominously filled by our enemies. He is on course to forsake Afghanistan as well," he said.

Meanwhile, Democratic leaders failed to pass a resolution supporting Obama's Iran nuclear deal when members of the Democratic National Committee met over the weekend for their summer meeting in Minneapolis, sources told the Washington Post.

The sources said Florida Rep. Debbie Wasserman Schultz, the committee chairwoman, blocked such a resolution from being discussed during the meeting.

Schultz did not explain the reason for her action just days before Congress votes on the issue on Sept. 17.

Meanwhile, Obama gained a new Democratic supporter for the deal when Sen. Jeff Merkley from Oregon announced on Sunday that he would support the nuclear agreement with Iran.

Merkley became the 31^st senator to express his support for the deal. Obama thus needs only three more votes in favour of the nuclear agreement to prevent the Senate from scrapping the deal with an override of Obama's expected veto.