European Union sanctions against Iran could be eased as soon as December, officials said Monday, after a potentially history-shaping deal that gives Tehran six months to increase access to its nuclear sites in exchange for keeping the core components of its uranium program.

The deal, announced Sunday, envisages lifting some of the sanctions that have been crippling the country's economy, and put in place over fears that Tehran is using its nuclear program to build atomic arms. Iran denies it wants such weapons.

"A Europe-wide decision is necessary" to ease EU sanctions on Iran, French Foreign Minister Laurent Fabius told Europe 1 radio. "That's expected in several weeks, for a partial lifting that is targeted, reversible."

"It could be in December, it could be in January, it depends on how long the legislative process takes," EU foreign affairs spokesman Michael Mann told reporters in Brussels.

The United States and the European Union have separate sanctions on Iran. Easing the European restrictions would affect numerous areas including trade in petrochemicals, gold and other precious metals, financial transfers to purchase food and medicine, and the ability of third countries to use EU-based firms to insure shipments of Iranian oil again.

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EU foreign affairs spokesman Michael Mann speaks to the media in Baghdad in May, 2012. (Khalid Mohammed/Associated Press)

Mann said work on amending the EU regulations was already beginning, but cautioned that changes depend on the Iranian government living up to its end of the deal.

"It's important that both sides of the bargain are implementing this agreement, so we would coordinate timing-wise also with the Iranian side," the EU spokesman said.

The agreement reached on Sunday will allow Iran to keep the central elements of its uranium program while stopping its enrichment at a level lower than what is needed for nuclear arms. In addition to a six-month window for Iran to allow more UN access to nuclear sites, sanctions will be eased — notably in the oil, automotive and aviation industries — though not ended.

The agreement is a first step — one that Israel has condemned as a "historic" mistake that effectively accepts Iran as a threshold nuclear weapons state. 

Reuters reported Israeli Prime Minister Benjamin Netanyahu said on Monday he is sending his national security adviser to Washington for talks on the final Iran deal.

Israel has found common cause with Saudi Arabia, which shares concerns about a nuclear-armed Iran and Tehran's growing regional influence. However, Saudi Arabia said Monday that the interim nuclear deal could be a step towards a comprehensive solution provided there was goodwill, Reuters reported.

On his return to Tehran, Iranian Foreign Minister Mohammed Javad Zarif told state television that the country was prepared for quick follow-up negotiations to keep the deal on track.

"We are ready to begin the final stage of nuclear agreement from tomorrow," said Zarif, who was greeted by hundreds of cheering students late Sunday.

Hard-liners remain skeptical

Many Iranians appeared upbeat about the deal and the possibility of an eventual end to sanctions, such as blocks on access to international banking networks that have crippled businesses and made once-routine transactions — such as paying tuition for a student abroad — a complicated process.

But hard-line groups remained highly wary of any close cooperation with Washington.

'We are ready to begin the final stage of nuclear agreement from tomorrow.'-  Iranian Foreign Minister Mohammed Javad Zarif

An editorial in the conservative daily Kayhan described the U.S. as a deceitful power that could renege on its pledges even if Iran sticks with its part of the deal.

"The U.S. was not trustworthy. The Geneva deal lasted only one hour," it said in its front-page headline, referring to U.S. Secretary of State John Kerry's comments that there was no recognition of Iran's "right" to enrich uranium.

Iran insists that trying to block enrichment was a dead end. For Iran's leaders, self-sufficiency over the full scope of its nuclear efforts — from uranium mines to the centrifuges used in enrichment — is a source of national pride and a pillar of its self-proclaimed status as a technological beacon for the Islamic world.

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Iranians hold posters of President Hassan Rouhani as they welcome nuclear negotiators upon their arrival from Geneva at the Mehrabad airport in Tehran on Sunday, Nov. 24, 2013. (Hemmat Khahi/ISNA/Associated Press)

In the end, Iran agreed to cap its enrichment level to a maximum of 5 per cent, which is well below the 90 per cent threshold needed for a warhead. Iran also pledged to "neutralize" its stockpile of 20 per cent enriched uranium — the highest level acknowledged by Tehran — by either diluting its strength or converting it to fuel for its research reactors, which produced isotopes for medical treatments and other civilian uses.

In return, Iran got a rollback in some sanctions — a total package estimated by the White House at $7 billion back into the Iranian economy — but the main pressures remain on Iran's oil exports and its blacklist from international banking networks during the first steps of the pact over the next six months.

The talks were also the culmination of a painstaking process of old-school contacts and secret sessions between Iranian and American envoys that began even before the surprise election of Iran's moderate-leaning President Hassan Rouhani last June.

The shadow dialogue, mediated by mutual ally Oman, was so sensitive that it was kept from even close allies, such as negotiating partners at the nuclear talks, until two months ago, according to details obtained by The Associated Press and later confirmed by senior administration officials. The pace of the back-channel contacts picked up after Rouhani officially took office in August, promising a "new era" in relations with the West.

CBC foreign correspondent Nahlah Ayed called the deal a "major boost" to the Rouhani government.

"He chose from the beginning to speak of a moderate approach, one that involves engagement, and he has been proven right by the fact that the deal has come through," Ayed said.  

With files from Reuters