President Donald Trump is leaning toward decertifying the Iran nuclear deal and putting the decision of whether the United States withdraw from the accord in the hands of Congress, according to four sources — including a senior administration official — familiar with the White House deliberations.

Such a move would come before an Oct. 15 deadline and would trigger a 60-day window for lawmakers to determine whether to reimpose sanctions related to Iran's nuclear program that were lifted as part of the 2015 agreement. The president's goal during that time is to prod America's European allies, who are part of the nuclear deal, to agree to renegotiate some provisions and pressure Iran back into talks.

Still, several of the sources cautioned that the president could change his mind over the next three weeks as he faces pushback from allies internationally.

Trump told reporters Wednesday that he has "decided" on a plan of action, but he declined to provide specifics. Asked for comment, a White House spokesperson said the president will announce further details when he's ready.

The senior administration official said that the president has resolved not to continue the "status quo" but that he's considering at least one other option related to the deal.

That option, according to two officials, would give European allies 90 days to get on board with renegotiation — rather than punt the decision to Congress. Administration officials are still in talks with those allies and with Republicans on Capitol Hill.

The White House has not responded to a request for comment.

Trump so far has twice recertified the Iran deal, despite having vowed to end it on the campaign trail. But this week, he ratcheted up his rhetoric, calling the agreement an "embarrassment" to the United States in his speech to the U.N. General Assembly in New York.

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The president is already facing international pressure not to withdraw. A British government official said Prime Minister Theresa May will raise her strong objections to pulling out of the joint agreement when she meets with Trump on the sidelines of the U.N. meeting. The official said that while Britain, France and Germany, known as the E3, acknowledge that the deal is not perfect, they believe it does reduce Iran's pursuit of nuclear technology and aggressive actions in the region.

And President Emanuel Macron of France, in an interview with CNN, warned that it would be a "big mistake" if the United States pulled out of the treaty.

Former Secretary of State John Kerry, who helped negotiate the deal in 2015, suggested that withdrawal could send the wrong message to Pyongyang as North Korea continues to ramp up its own nuclear program.

"If you go after the Iran deal and Iran the way [Trump] did yesterday and you talk about throwing it out, you make your diplomatic efforts of solving North Korea far more complicated," he said on MSNBC's Morning Joe. "What does North Korea think, looking at the way he's talking about shredding a deal that was made?"

Related: Trump Drive to Ax Iran Nuclear Pact May Alienate Allies

But "the issues surrounding North Korea are very different from the issues surrounding Iran," Secretary of State Rex Tillerson told reporters Wednesday night.

"The end points are the same, but the elements that allow you to achieve that are very, very different," Tillerson said.

The top U.N. inspection officials in Vienna said Iran has complied with the nuclear deal, and President Hassan Rouhani insists that Iran will not renegotiate. He told NBC's Lester Holt that "no one will trust America" again if Trump backs out of the agreement.

But Tillerson said Wednesday night: "We clearly have significant issues with the agreement. The president has been quite clear, particularly as to his concerns about the agreement itself, the thoroughness of the agreement, the enforcement of the agreement.

While Tillerson acknowledged that the technical aspects of the deal had been met, he said the administration had broader political concerns.

"Regularly since the agreement has been confirmed, we have seen anything but a more peaceful and stable region," he said.

Air Force Gen. John Hyten, commander of U.S. Strategic Command, said Wednesday that Iran is observing the terms of the nuclear deal and that it's the United States' job to live up to the agreement, as well. But he also said Iran is "rapidly deploying and developing a whole series of ballistic missiles" that concern the United States and its allies.

Foreign Minister of Iran, Mohammad Javad Zarif shakes hands with U.S. Secretary of State John Kerry at the last working session of E 3+3 negotiations on Jul. 14, 2015 in Vienna, Austria. Thomas Imo / Getty Images file

"Why are they doing that? To challenge the United States and our allies down the road," Hyten said. "We have to figure out how to respond."

The so-called sunset provisions in the nuclear agreement are a particular sticking point. Those clauses allow some of the deal's restrictions on Iran's nuclear program to wind down over time.

The White House is also pushing for tougher inspections on Iranian nuclear sites, which would require U.N. and European support.