The most powerful pro-Israel lobbying group in the United States has called on the US Congress to reject the nuclear conclusion reached between Iran and the P5+1 group of countries on Tuesday in Vienna, Austria.

"Unfortunately, this proposed agreement fails to halt Iran's nuclear quest," the American Israel Public Affairs Committee (AIPAC) said in a statement issued on Wednesday.

"Instead, it would facilitate rather than prevent Iran from obtaining a nuclear weapon," it added.

After 18 days of talks in Vienna, Iran and the P5+1 group - the United States, Britain, France, China, Russia and Germany - reached a conclusion on the Joint Comprehensive Plan of Action (JCPOA), which will put limits on Iran’s nuclear program in exchange for the removal of sanctions against the Islamic Republic.

The 159-page JCPOA agreement has been presented to the UN Security Council, which will likely adopt a resolution next week making the JCPOA an official document.

The US Congress now has 60 days to review the text and vote to either approve or disapprove of it. President Barack Obama said on Tuesday that he would veto any legislation from lawmakers that "prevents the successful implementation of the deal."

US President Barack Obama (R) and Vice President Joe Biden walk from the Green Room to speak on the conclusion of Iran nuclear talks on July 14, 2015 at the White House in Washington, DC. (AFP photo)

According to the JCPOA text, Iran will be recognized by the United Nations as a nuclear power and will continue its uranium enrichment program.

On Tuesday, Israeli Prime Minister Benjamin Netanyahu described the agreement on Tehran's nuclear program as "a historic mistake" and said he would do everything he could to block it.

According to the Washington Examiner, the AIPAC statement declared “the proposed agreement has significant flaws."

The statement pointed out that the nuclear accord does not give permission to inspectors to inspect Iranian nuclear sites "anytime, anywhere"; does not condition lifting of sanctions toward verifying Tehran meet demands on the possible military dimensions of its nuclear program; it starts to remove sanctions immediately; it lifts restrictions in eight years; and doesn't dismantle any nuclear centrifuges.

"This accord threatens the future of the nuclear non-proliferation regime," the statement claimed.

"We strongly believe that the alternative to this bad deal is a better deal. Congress should reject this agreement, and urge the administration to work with our allies to maintain economic pressure on Iran while offering to negotiate a better deal that will truly close off all Iranian paths to a nuclear weapon. Congress should insist on a better deal,” it continued.

The Israeli nuclear facility in the Negev Desert outside Dimona. (file photo)

Israel and some of its allies accuse Iran of pursuing military objectives in its nuclear energy program.

Iran rejects the allegation, arguing that as a committed signatory to the nuclear Non-Proliferation Treaty (NPT) and a member of the International Atomic Energy Agency (IAEA), it has the right to use nuclear technology for peaceful purposes.

Israel, which has rejected global calls to join the NPT and does not allow international inspectors to observe its nuclear program, is widely believed to be the sole possessor of a nuclear arsenal in the Middle East with about 400 undeclared nuclear warheads.