Iran suspended part of its uranium enrichment efforts Monday, and the U.S. and European Union began loosening some economic sanctions, the first concrete steps toward a comprehensive deal to end the long confrontation over Tehran's nuclear ambitions.
But even as a six-month interim accord began on schedule, opposing sides differed sharply on the implications of what had been achieved as they tried to win over skeptics at home.
Iran's leaders, eager to sell their economically beleaguered public on the benefits of nuclear negotiations, said the agreement would open the way to a surge of international trade and investment.
"The window of opportunity for Iran's trade with Europe will increase tenfold" once the deal is fully in place, Abbas Araqchi, Iran's chief nuclear negotiator, told the official Islamic Republic News Agency. "The private sector of Iran will have a great share of trade with the European Union."
Ali Akbar Salehi, head of Iran's nuclear agency, struck an even more triumphal tone: "The iceberg of sanctions is melting while our centrifuges are also still working," he said on state television. "This is our greatest achievement."
U.S. officials, keen to rebut criticism among some lawmakers and others that the deal negotiated in November gave up too much to the Iranians, insisted that the sanctions relief was small in scale and easily reversible if Iran reneged. They stressed that other crippling restrictions on Iran's economy remain in place.
Unless the two sides reach a final agreement this year designed to prevent Iran from gaining the ability to build nuclear weapons, the full raft of sanctions against Iran's economy won't be lifted, the Los Angeles Times reported, citing an unnamed senior official.
The six-month agreement, signed Nov. 24 by Iran and six world powers — the United States, Russia, China, Britain, France and Germany — was designed to buy time to negotiate a more permanent accord. It calls for Iran to roll back parts of its nuclear program in exchange for limited relief from international sanctions. Though scheduled to last six months, the deal can be renewed for another six as the two sides talk.
Iran says its nuclear efforts are strictly for peaceful purposes, including energy generation and production of medical isotopes for cancer treatment. The United States and other nations fear the real goal is to develop a nuclear weapon, leading to the series of sanctions that have helped saddle Iran with high unemployment, galloping inflation, a collapsing currency and widespread public discontent.
Tehran's nuclear program is just one of many issues that have raised concern among Western officials. Iran backs Syrian President Bashar Assad as he faces a nearly 3-year-old rebellion supported by the U.S. and its allies, and is a key backer of the Hezbollah movement in Lebanon.
The carefully choreographed first steps of the interim agreement began Saturday when inspectors from the International Atomic Energy Agency, or IAEA, arrived in Iran to oversee implementation.
On Monday, Iranian officials said they had disconnected centrifuges at two of the nation's nuclear sites, Natanz and Fordow, fulfilling the requirement to end production of uranium enriched to 20 percent, a medium level of purity.
In a statement reported by Press TV, Iran's official English-language news service, Salehi said the Islamic Republic had started to "voluntarily suspend" medium-level enrichment in compliance with the accord.
The IAEA submitted a report to Washington and Europeans that "verified that Iran has fulfilled its initial nuclear commitments," the State Department announced in a statement.
In response, the United States and 28-member European Union lifted restrictions on Iran's sales of petrochemicals and allowed resumption of trade in gold and precious metals and transactions with Iran's automotive sector. The U.S. also began steps toward allowing Iranian airlines to buy spare parts and obtain maintenance services.
Some restrictions on Iran's oil industry also will be rolled back, allowing access to maritime insurance, seen as a necessity before oil tankers can take to sea.