Capping exhausting and contentious talks, Iran and world powers sealed a breakthrough agreement Thursday outlining limits on Iran's nuclear program to keep it from being able to produce atomic weapons. The Islamic Republic was promised an end to years of crippling economic sanctions, but only if negotiators transform the plan into a comprehensive pact.

They will try to do that in the next three months.

The United States and Iran, long-time adversaries who hashed out much of the agreement, each hailed the efforts of their diplomats over days of sleepless nights in Switzerland. Speaking at the White House, President Barack Obama called it a "good deal" that  "meets our core objectives" and would address concerns about Iran's nuclear ambitions. Iranian Foreign Minister Mohammad Javad Zarif called it a "win-win outcome."

America's negotiating partners in Europe strongly backed the result. President Francois Hollande of France, which had pushed the U.S. for a tougher stance, endorsed the accord while warning that "sanctions lifted can be re-established if the agreement is not applied."

'If Iran cheats, the world will know it'

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U.S. President Barack Obama speaks about the breakthrough in the nuclear talks with Iran. A tentative agreement was reached on Thursday. (Susan Walsh/Associated Press)

Obama said verification mechanisms built into the framework agreed to in Switzerland hours earlier would ensure that "if Iran cheats, the world will know it."

According to a U.S. fact sheet, the agreement includes: 

  • Iran significantly reducing the number of installed uranium enrichment centrifuges it has to 6,104 from 19,000 and only operating 5,060 under a future comprehensive nuclear deal with six powers
  • Iran gradually receiving relief from U.S. and European Union nuclear sanctions as it demonstrates compliance with a future comprehensive nuclear agreement, which Iran and six world powers aim to conclude by June 30
  • Failure to comply with terms of the deal will cause those sanctions to "snap back into place."
  • Robust inspections of Iran's uranium supply chain to last for 25 years if the deal is agreed upon.

Canadian sanctions stay in place

​James Bezan, the parliamentary secretary to the defence minister, told CBC News Network's Power & Politics that Canada would only consider lifting sanctions against Iran if it is sure the country is "finally and honestly" demilitarizing its nuclear program.

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Iranian Foreign Minister Javad Zarif called the tentative deal a 'win-win outcome.' (Brendan Smialowski/Associated Press)

"Until then, we are going to be very conscientious and skeptical of the outcome here," Bezan said.

Foreign Affairs Minister Rob Nicholson said the government appreciates" the efforts of the P5+1 in these discussions. At the same time, we will continue to judge Iran by its actions and not its words.

"Iran's track record is not one that encourages trust."

Opponents of the emerging accord, including Israel and Republican leaders in Congress, reacted with skepticism. They criticized the outline for failing to do enough to curb Iran's potential to produce nuclear weapons or to mandate intrusive enough inspections. Obama disagreed.

"This framework would cut off every pathway that Iran could take to develop a nuclear weapon," he declared. "This deal is not based on trust. It's based on unprecedented verification."

Obama spoke by telephone with Israeli Prime Minister Benjamin Netanyahu, perhaps the sharpest critic of the diplomacy with Iran. The White House said Obama told Netanyahu that the agreement "in no way diminishes our concerns with respect to Iran's sponsorship of terrorism and threats towards Israel."

'Threaten the survival of Israel'

But Israel's prime minister said he has voiced his "strong opposition" to the world's framework nuclear agreement, and  said a final deal based on this agreement "would threaten the survival of Israel."

He said the deal would legitimize Iran's nuclear program and increase Iranian "aggression and terror."

But Obama saved his sharpest words for members of Congress who have threatened to either try to kill the agreement or approve new sanctions against Iran. Appearing in the Rose Garden, Obama said the issues at stake are "bigger than politics."

"These are matters of war and peace," he said, and if Congress kills the agreement, "international unity will collapse, and the path to conflict will widen."

U.S. House Speaker John Boehner said it would be "naive to suggest the Iranian regime will not continue to use its nuclear program, and any economic relief, to further destabilize the region."

Freshman Republican Senator Tom Cotton, who penned a letter that many GOP senators signed last month to Iran's leaders, said he would work "to protect America from this very dangerous proposal."

In a joint statement, European Union foreign policy chief Federica Mogherini and Iran's Zarif called the agreement a "decisive step." Highlighting Iran's effort to show a new face of its government, Zarif then held a news conference, answering many questions in English, and Obama's statement was carried live and uncensored on Iranian state TV.

Still, all sides spoke with a sense of caution.

"We have taken a major step, but are still some way away from where we want to be," Zarif told reporters.

Zarif said the agreement would show "our program is exclusively peaceful, has always been and always will remain exclusively peaceful." But he also said it would not hinder the country's pursuit of atomic energy for civilian purposes. "We will continue enriching," he said. "We will continue research and development."

With files from Reuters