Donald Trump's election as president raises the prospect the United States will pull out of the nuclear pact it signed last year with Iran, alienating Washington from its allies and potentially freeing Iran to act on its ambitions.
Outgoing President Barack Obama's administration touted the deal, a legacy foreign policy achievement, as a way to suspend Tehran's suspected drive to develop atomic weapons. In return Obama, a Democrat, agreed to a lifting of most sanctions.
The deal, harshly opposed by Republicans in Congress, was reached as a political commitment rather than a treaty ratified by lawmakers, making it vulnerable to a new U.S. president, such as Trump, who might disagree with its terms.
A Republican, Trump ran for the White House opposing the deal but contradictory statements made it unclear how he would act. In an upset over Democrat Hillary Clinton, Trump won on Tuesday and will succeed Obama on Jan. 20.
A businessman-turned-politician who has never held public office, Trump called the nuclear pact a "disaster" and "the worst deal ever negotiated" during his campaign and said it could lead to a "nuclear holocaust."