Nikki Haley, US ambassador to the United Nations, said that Tehran is complying with the 2015 nuclear accord intended to increase Iran's accountability in return for the lifting of some economic sanctions.
"I think right now, you're going to see us stay in the deal," Haley told NBC's "Meet the Press."
In a speech on Friday, Trump laid out an aggressive approach on Iran and said he would not certify it is complying with the nuclear accord, despite a determination by the United Nations' nuclear watchdog that Tehran is meeting its terms.
The Republican president threw the issue to the U.S. Congress, which has 60 days to decide whether to reinstate US sanctions. He warned that if "we are not able to reach a solution working with Congress and our allies, then the agreement will be terminated."
So far, none of the other signatories to the deal - Britain, France, Germany, Russia, China, Iran and the European Union - have cited serious concerns, leaving the United States isolated.
In her "Meet the Press" interview, Haley said the United States was not saying that Iran was in breach of the agreement, but she raised concerns about its activities that are not covered by the pact, including weapons sales and sponsorship of militant groups such as Hezbollah.
Haley said that other countries were "turning a blind eye" to these Iranian activities in order to "protect" the nuclear agreement.
She said the United States needed to weigh a "proportionate" response to Tehran's actions on the world stage.
"The goal at the end of the day is to hold Iran accountable," Haley said in the interview, which mainly focused on the Joint Comprehensive Plan of Action, as the nuclear deal is formally known.
Haley and US Secretary of State Rex Tillerson hammered away at the need to address what they see as shortcomings in the two-year-old international accord while simultaneously placing pressure to rein in Iranian activities outside the scope of that deal.
A Second Pact?
Haley also said the reason the United States was looking closely at the Iran nuclear deal is because of escalating tensions over North Korea's nuclear weapons development. "What we're saying now with Iran is don't let it become the next North Korea."
On Friday, Trump also said he was authorizing the US Treasury to sanction Iran's Revolutionary Guards, and on Sunday Treasury Secretary Steven Mnuchin said he was planning to move ahead.
Mnuchin, interviewed on Fox News' "Sunday Morning Futures," said he has spoken about Iran with his counterparts attending World Bank and International Monetary Fund meetings in recent days.
He did not provide any details on possible sanctions.
US Senator Susan Collins, appearing on ABC's "This Week," noted that Trump could have taken a more extreme step by withdrawing from the agreement.
But in words of support for Trump, the moderate Republican lawmaker said, "Instead, he put a spotlight on two troubling deficiencies in the agreement," referring to a lack of limitations on Iran's tests of ballistic missiles and a "pathway to developing a nuclear weapon" down the road.
While many US allies strongly criticized Trump's decision not to recertify the Iran deal, Israeli Prime Minister Benjamin Netanyahu praised the move, saying the current terms of the Iran nuclear accord would allow it to have a nuclear stockpile within a decade.
"We cannot allow this rogue regime 30 times the size of North Korea's economy to have a nuclear arsenal," Netanyahu said on CBS' "Face the Nation."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)