This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.VIENNA — After arduous talks that spanned 20 months, negotiators have reached a landmark deal aimed at reining in Iran’s nuclear program. The agreement, a focal point of U.S. President Barack Obama’s foreign policy, appears set to reshape relations between Iran and the West, with its effects likely to ripple across the volatile Middle East. Representatives of Iran, the United States and the other nations involved in the marathon talks were holding a final meeting in Vienna on Tuesday. Obama praised the deal reached Tuesday morning, saying the agreement met the goals he had in place throughout negotiations. “Today after two years of negotiation the United States together with the international community has achieved something that decades of animosity has not: a comprehensive long-term deal with Iran that will prevent it from obtaining a nuclear weapon,” Obama said from the White House, with Vice President Joe Biden at his side. Iranian President Hassan Rouhani also praised the deal, speaking after Obama finished, as televisions in Iran broadcast the U.S. President’s statement live, translated into Farsi. “Negotiators have reached a good agreement and I announce to our people that our prayers have come true,” Rouhani said in a live address to the nation following Obama. The essential idea behind the deal is that in exchange for limits on its nuclear activities, Iran would get relief from sanctions while being allowed to continue its atomic program for peaceful purposes. After news of the deal emerged, Yukiya Amano, the chief of the International Atomic Energy Agency, said he had signed a “roadmap” with the Iranian government “for the clarification of past and present outstanding issues regarding Iran’s nuclear program.” Far from over But the deal between Iran and world powers, brokered during lengthy negotiations in a Vienna hotel, is far from the end of the story. Details on what terms were agreed on key technical issues weren’t immediately available Tuesday. The accord is expected to face fierce opposition from Republicans in the U.S. Congress, as well as from Israeli Prime Minister Benjamin Netanyahu, a longstanding critic of the negotiations. “From the initial reports we can already conclude that this agreement is a historic mistake for the world,” Netanyahu said Tuesday. “Far-reaching concessions have been made in all areas that were supposed to prevent Iran from obtaining nuclear weapons capability.” Netanyahu has repeatedly warned of Iranian support for terrorism and its ambitions to expand its influence and annihilate Israel. Congress has 60 days to review the agreement, giving its opponents plenty of time to dig into the details and challenge the Obama administration’s position. In Tehran, the deal will need the clear backing of Iran’s supreme leader, Ayatollah Ali Khamenei, to fend off any objections from hardliners suspicious of an accord with the United States after decades of hostility and mistrust. Rouhani said on Twitter that the deal shows that “constructive engagement works.” “With this unnecessary crisis resolved, new horizons emerge with a focus on shared challenges,” he tweeted.