WASHINGTON • The landmark Iran nuclear agreement is widely seen as President Barack Obama's hallmark foreign policy achievement, but President-elect Donald Trump has called it a "horrible deal". That has prompted the Obama administration to take further steps to bolster it before Inauguration Day.
Iran and the UN Security Council's five permanent members the United States, France, Russia, China and the United Kingdom, plus Germany, reached and endorsed the agreement in July 2015 and adopted it three months later.
The Obama administration says that before the deal Iran would have been two to three months away from building a nuclear bomb, but that after the deal the "break out" time has been extended to a year.
Mr Obama said in January last year that "with the world's unprecedented inspections and access to Iran's programme, we'll know if Iran ever tries to break out" and produce a nuclear weapon.
That same month, the International Atomic Energy Agency verified that Iran had completed the necessary steps to ensure that its nuclear programme remains peaceful, and the US and other countries began lifting nuclear-related sanctions.
After the election in November last year, the US government said it had issued a second licence for the sale of Airbus planes to Iran Air as part of the deal to ease sanctions.
On the sidelines of the Iran nuclear negotiations, the Obama administration also negotiated the release of several Americans detained by Iran, and six Iranian-Americans and one Iranian were granted clemency.
Said Mr Obama in January last year: "We can leave this world and make it safer and more secure for our children and our grandchildren for generations to come."
Republicans however, continue to oppose the deal, refusing to trust Iran. They believe that the lifted sanctions provide a financial injection for Iran's military and terrorist allies. In November, House Speaker Paul Ryan, Majority Leader Kevin McCarthy and foreign affairs committee chairman Ed Royce wrote to Mr Obama urging him "not to take any action that would weaken United States or multilateral sanctions or other restrictions against Iran in the post-election period".
While most await to see what the new administration will do about the deal, experts say years of negotiations could easily be overturned by Mr Trump.