A Republican majority in the US House of Representatives will vote to block the Iran nuclear deal, a lawmaker announced Monday, but in numbers shy of the two-thirds required to torpedo the accord.

Congress will vote before September 17 on a resolution of disapproval of the agreement that six world powers reached with Tehran last month.

If the resolution is adopted, it would prevent President Barack Obama from lifting crippling US sanctions against the Islamic republic in exchange for the rollback of Iran's nuclear program.

Republicans control both the House and Senate, and such a motion appears on track to pass both chambers -- but Obama would veto it.

Overcoming the presidential veto would require a two-thirds majority in both chambers, a difficult challenge if most Democrats remain loyal to the president.

House Republican Peter Roskam said Monday that 218 of the 434 current members have committed to voting for the disapproval resolution which he introduced in July.

All are Republicans, and to date some in the party have yet to express their backing.

"Congress and the American people believe a better agreement is still achievable, and we can start by walking away from this one," Roskam said.

"We will do everything in our power to stop an accord that so utterly fails to shut down Iran's nuclear program."

On the Democratic side, several key lawmakers -- fervent allies of Israel -- have remained quiet on the accord, including Senator Chuck Schumer of New York and congressman Eliot Engel, top Democrat on the House Foreign Affairs Committee.

Some figures like Nancy Pelosi, the top House Democrat, have expressed unequivocal support for the deal.

The current House breakdown is 246 Republicans and 188 Democrats. A Republican seat is vacant and will be filled in a September 10 election, bringing the total again to 435 representatives.

The two-thirds threshold is 290.

The Senate, where the two-thirds threshold is 67, consists of 54 Republicans and 46 on the Democratic side, including two independents.

Iran official urges quick approval of nuclear deal
Tehran (AFP) Aug 1, 2015 - Iran's deputy foreign minister Saturday urged a speedy approval in Tehran of a nuclear deal so blame for any failure falls on US lawmakers who may yet vote against it.

Abbas Araghchi's comments come as US Secretary of State John Kerry and members of his nuclear negotiating team are being grilled in Congress two weeks into a 60-day review of the deal in Washington.

A similar process is under way in Iran's parliament, where some MPs have argued that the agreement has jeopardised the country's nuclear programme.

The deal between Iran and six world powers led by the United States must be approved by Iran's top security committee and parliament before it can be finally implemented.

"We should announce our opinion quickly so if the Congress decided to reject the deal, the onus of such rejection and failure of talks would fall on Congress," Araghchi said, not naming lawmakers but signalling the need for their endorsement.

"In that case we will not suffer any losses and we can return to our normal programme," he told Iranian state television's political editors.

"Then the world would say that Iran went through its legal process and approved the agreement yet the Congress destroyed the whole thing."

Kerry has said it would be embarrassing to him and a blow to American credibility on the world stage if the Republican-led Congress rejects the deal to put an atomic bomb out of Iran's reach.

Iran has always denied seeking a nuclear weapon.

President Barack Obama can veto Congress and keep the deal alive as long as US lawmakers do not obtain a two thirds majority vote.

Araghchi, effectively the number two negotiator for Iran in the nuclear talks behind Foreign Minister Mohammad Javad Zarif, spoke ahead of President Hassan Rouhani's live televised speech on Sunday night which is expected to focus on the nuclear deal.

Israel and other opponents believe the agreement, struck in Vienna on July 14, does not achieve its primary objective of mothballing Iran's nuclear programme and closing all paths to a bomb. Obama's White House says it does exactly that.

However Rouhani's government has been trying to convince conservatives that the concessions made in the deal are not detrimental to its ambitions of producing nuclear energy, saying that the sanctions relief is worth the limitations.

However despite Araghchi's call for a speedy rubber stamp, Iranian lawmakers are believed to be awaiting the outcome of Congress's review before they announce their final opinion.

Iran bans newspaper of nuclear deal critic, warns others
Tehran (AFP) Aug 3, 2015 - Iran banned a weekly newspaper owned by a critic of its nuclear deal Monday and issued a formal warning to the country's leading conservative daily for alleged breaches of reporting guidelines.

The penalties were the first issued by the government since new guidance on media coverage of the historic accord was issued last week, underscoring sensitivity about the nuclear issue in Tehran.

The Press Supervisory Board banned "9th Dey Weekly", managed by ultra-conservative lawmaker Hamid Rasaie and named after the Persian calendar date of a major pro-government rally on December 30, 2009.

It also gave warning notices to the Kayhan daily and another outlet, the Raja news website.

All are alleged to have insulted Iranian officials as well as violating orders on coverage of the deal issued by the Supreme National Security Council (SNSC).

The SNSC is the country's highest security committee and it oversees the nuclear talks under the auspices of supreme leader Ayatollah Ali Khamenei.

On July 14, Iran and the United States along with Britain, China, France, Russia and Germany reached an agreement to end the nuclear dispute with Iran.

Under the deal Iran has agreed to curbs on some of its nuclear activities in exchange for a lifting of international sanctions imposed in recent years.

Iran has always denied Western allegations that it aims to develop an atomic weapon and says its nuclear programme is for peaceful energy production.

The official IRNA news agency reported the media ban and warnings. Quoting the Press Supervisory Board it urged domestic media to consider "national interests and security and carry out criticism in the framework of responsible freedom".

"If anyone was to make comments against our national interests on a subject that is tied with our national security, it should definitely be stopped," said Hossein Noushabadi, a culture ministry spokesman.

The nuclear agreement is "an important matter that was achieved under the supervision of the supreme leader... and cannot be easily criticised with unjust comments," he added.

Rasaie said he was disappointed by the suspension.

"The banning of 9th Dey Weekly under (President Hassan) Rouhani's government is no strange news," the lawmaker wrote on his Instagram page.

It is the third time the publication has been banned over its coverage of the nuclear issue.

On the two previous occasions -- after an interim agreement in November 2013 and then again earlier this year -- the ruling was overturned.

"This government has proven much less tolerant of criticism than it claims," Rasaie said.

Conservative media in Iran have poured scorn on the deal.